Thoughts on over skimming
 

Anyone have experience on over skimmed tanks? I'm starting to think my tank is being over skimmed as I'm noticing a decline in some LPS coral health. SPS corals are doing well with good color but LPS corals like acans, brains and lobos are beginning to suffer. I've always noticed that LPS corals do better in tanks with more organics and SPS corals are the opposite. In order to find a healthy balance I'm considering running my skimmer on a timer to only skim overnight.

Any thought or experience would be helpful. I run a BK SM 250 on a 120 gallon system.

Do you have any remaining nuisance algae?

I have noticed on tanks that I considered to be over-skimmed that coralline, pods, and micro-inverts (like spirodid worms, mini feather dusters, etc) all but died off. I have also noticed that it's difficult to keep SPS and LPS in the same tank and have them all equally healthy and bright without fairly heavy feeding. Do you feed the corals any meaty foods or additives like Zeo or Fauna Marin? I have really noticed an improvement in LPS since I started using Coral Vitalizer and Sponge Power.

I'm going to go over to the Zeo forums and ask a similar question as I've been meaning to for awhile. As I have gotten quite quickly into SPS lately (since my lights were burning the LPS) I have been getting more and more into Zeo and I worry about the future of the currently healthy LPS due to the forthcoming ultra low nutrient system. I will report back if you'd like.

I severly overskim my tanks and got fantastic results, remember if you are over skimming you have to pay closer attention to your water peramiters, and make sure your compensate your feeding, ie feed more often or feed more as good skimming will remove waist food faster.

I had LPS and SPS, worms, Pods. which thrived in my overskimmed tanks, and had to scrape coraline algae off the glass every day, so I don't think overskiming is your problem as much as water peramiters/light/ect.

My Brain grew from a 3" base to a 6" base in about 6 months, mushroom became such a problem I had to remove them as they were taking over, and SPS gave me amazing growth rates.. all while using a skimmer that was probably rated for 6X the system volume of water. I ran the skimmer so it made a fairly dry foam, ran a Co2 reactor, Kalk reactor, sever water flow (aprox 120X turnover) but I did run a slightly elivated Alk, I liked 1.026 for salinity, 11 to 12Dkh, about 380 to 400 Ca, 1400 Mg, and my Ph was always around 7.9 I ran two AB 10K SE bulbs driven by M80 ballasts on a 3 foot tank plus two 3 foot VHO actinic bulbs overdriven about 14%. the tank was bare bottom, but I built Pod piles behind the rock work. I find the bigest mistake people make is not building pod piles as this gives them a place to grow with out worry of preditation. I had two mandrins and they always were eating pods which I feel was due to the pod piles as they mandrens can't get into them, so the pods can reproduce like mad and as the populatin increases they spread through out the tank.

Steve

I do have a few kinds macro algae kicking around still, but nothing serious. I don't really have much that eats it though but it is slowly decreasing. For the most part this algae is limited to the back pane and a small section of rock at the front of the tank. The rest of the rock is bare with no forms of algae. Coraline is very limited, I maintain a lower Ca (400) and Alk (8) than most and I've avoided introducing coraline as I'm not a huge fan, it's hard to clean and can become overwhelming. Pod population is good but the other stuff is limited, the tank is still fairly new and the rock was cleaned and re-cured from my previous setup so the transfer was also limited.

I do feed some meaty foods from time to time and I probably should be more aggressive but I've found lately that feeding tentacles are not showing up as often. Also some LPS corals are still doing well, such as dendo, chalice, trumpet, duncan, and closed brains. I try to avoid those power foods and I think they tend to do more harm than good but would be willing to use them again if results would improve. I definitely would consider dosing some zeo products again like LPS amino but currently I'm not dosing anything of the sort and would prefer to find the root of the problem first and then add certain things for further improvement.

If you do post on Zeo and get some relative information please let me know and send me a link. That would be much appreciated.

What water parameters are you referring to? Anything I can test seems fine and I do 10% weekly water changes with RB salt. I don't have heavy light in my tank and I keep my LPS lower or in shady areas. The LPS did fine at first but lately a decrease in health in some is obvious.

From my experience higher nutrients results in healthier LPS, my first reef tank was an LPS tank, basically skimmerless and I never fed them, never have I had LPS corals as healthy as they were in that tank.
http://i11.photobucket.com/albums/a1...ishtank064.jpg


I'm willing to sacrifice some SPS color for healthier LPS, i would actually prefer to keep a more LPS dominant tank. Can any one see any potential problems resulting from running a skimmer on a half duty cycle over night?

Low nutrient levels will cause a decline in LPS health, but it is not necessarily caused by your protein skimmer. It is more likely an issue tied to nutrient export such as water changes, algae harvesting, and other chemical filtration methods like carbon and ion exchange resins.

LPS & SPS don't readily mix in nature, so our expectations are generally over-optimistic when it comes to a mixed captive reef. Target feeding may be the only compromise of supply and demand.

There is some debate whether or not carbon is the limiting factor for coral health and growth. My guess is that carbon dosing fosters the growth of microorganisms that feed corals and consume nutrients, rather than bacteria that consume nutrients.

Well i don't run carbon so would you consider running the skimmer at 0.5 duty, cutting water changes to 5% weekly and preventing algae growth a good initial approach to the problem?

I don't see a problem with cutting back on protein skimming hours, especially if you don't have nuisance algae problems or high nutrient levels. If the LPS that you want to focus on are night feeders like Acanthastrea & Lobophyllia then maybe skimming during the day will be better for SPS and not skimming at night will offer more available food for night feeding LPS.

What are your nitrate and phosphate levels now? While protein skimmers are very efficient at removing protein, they will allow heavy metals to accumulate. If your nutrient levels are above zero, it's possible that the LPS are adversely affected by heavy metal accumulation.

The other approach would be to maintain your filtration as is, and do more indirect feeding with Phytoplankton.

I thought about skimming in the day for that reason but I'm worried about oxygen levels dropping too low overnight. My powerheads slow down at night and my return is herbie style.

Those levels are not detectable with my test kits.

How low does your PH drop at night. Your tank is well stocked so there must be significant coral respiration at night that would add a lot of Co2. A reverse photoperiod refugium would keep your nightly dissolved oxygen rates high and balance PH if that in fact is an issue.

I have mixed feelings about cutting back flow at night. On one hand it replicates natural reef conditions and allows plankton to get around better at night, but on the other hand it may lower dissolved oxygen, make it harder to off-gas Co2, and higher flow may be better for feeding extended night feeders.

Whatever you are doing right to keep phosphate and nitrate at zero appears to be great for your SPS, and not so good for LPS. I would guess that it's the low nutrients and not high toxic metal concentrations that are limiting LPS success.

Rather than limit what you are doing right (nutrient reduction & export through protein skimming and water changes), I would increase nutrient import with Phytoplankton, rotifers and whatever you prefer to feed. I've read a few threads on RC about dosing phosphate and nitrate, but I think they should be added via food, not chemically.

I maintain calcium and alkinity only slightly higher than you...I don't think that would be any issue at all. You're still very close to NSW.

Not seeing feeding tentacles is definitely a poor sign. Ime, the LPS that aren't putting out their feeders are the ones that are past the point of being hungry and are now starving. Of course there could be other reasons too, but I really think you need to feed them more. I actually haven't tried the Zeo AA LPS yet...I keep forgetting about that one. :o

Where you said "power" did you mean "powder"? If so, I wouldn't bother. I think those powdered foods are great for polluting the tank and not much more. However, I do like to use Coral Frenzy when my Favia has all its tentacles out I will mix a very small amount of CF with saltwater and let it soak for 10 mins so it doesn't float, then turkey baste it over the Favia's tentacles. It seems to appreciate that, but I don't do that very often.

I put a post on Zeo forums, but there is only one reply so far, and it suggests no issues: http://www.zeovit.com/forums/showthread.php?t=18221

the first thing that pops out to me is "I don`t have heavy light in my tank".

the reason this is jumping out at me is you have to think of LPS like SPS but more flesh. yes they will do good under low light if they are fed, but when you are skimming heavily how are they getting fed? when you have intense lighting just like a SPS they will expell symbiotic algae as they don't need as many to create food for them other wise they need food by being fed directly or by adsorbing it from the water colum.. if you don't target feed frequently, or like dirty water :mrgreen: then you need enough light to sustain them. take my open brain as an example.. when I was running PS and VHO he was about 3" dia at the base (6" when expanded) and would eat 1 or 2 krill a day as I upgraded the lighting he started taking less food then it got to the point I could put mysis all over him and he wouldn't feed, but he kept growing and getting more color. when I had the tank melt down (heater got stuck on in a temp tank when I was removing the sand bed) he had a skeliton of 6 to 7" dia and would be almost 14" when expanded but he hadn't taken food in over 6 months. I could only conclude that he was getting all the food he needed from his internal algae and the lights.

so would I recomend overskimming with lower light power.. nope, you want crystal clean water you need plenty of light power.

Steve

I updated the firmware on my controller the other day which seems to have reset the stored calibration numbers, I need to recalibrate to get a more recent reading but I believe it drops to around 7.8 but will check later.

I know what you mean about the lower flow at night but the power heads only cut back to 30% so they still move a little water and i still have 10X through the return :wink: I mainly cut it back because it makes a little quiet time for the seahorse which takes full opportunity to come out and swim a little each night.
I'm not really into the refugium thing right now, I'm trying to keep things simple and clean with this tank and I think the it will create more complication than benefit. Personally I think running the skimmer at night might be a better option than the day. The skimmer is also the only part of the tank that makes any real noise, if the only time it's on is when I'm sleeping I can see that itself being a significant benefit.

I can always turn the skimmer off while I'm feeding. During feeding of any sort I always activate a feeding pause which shuts off everything for 20min, and the skimmer has an additional delay of 30min.

I'm going to experiment and shut the skimmer off during the day, it's large enough that I don't see the need for it anyway and I can always turn it back on at anytime. I'll cut back water changes, work on the algae, feed more and try dosing some stuff like phyto (live or processed btw??) and some zeo products.

Thanks for the link, I'll keep an eye on it. Yeah I meant powder, right now I'm not sure if the pollution it causes would be bad or good.

I don't know if doing all of these things at once is a good idea, I understand the reasoning but if things turn around would you not still be unsure as to which particular change you made produced the end result?

Use whatever phyto you can find that isn't overloaded with heavy metals, or trace elements as we call them.

The nightly PH drop is hard on certain corals like xenia and most SPS, but not so much with LPS. You could have secondary metabolites (allelopathy) stressing out the LPS. You will definitely have more once you shut down the skimmer.

I agree that adding a refugium just to regulate night PH drops isn't worth the negative aspects (tinted water, secondary metabolites, and further nutrient depletion). If your nutrient levels are already at zero, a refugium doesn't offer you much for the hassle. You could consider growing xenia or whatever grows best for you, in the sump on a reverse photoperiod. It would export heavy metals and pay for the extra food you will be adding :)

Running the skimmer at night will at least assure you are oxygenating the water as much as you can. My suggestion of shutting it off at night may not work so well in that respect.

What's you reasoning on not using carbon? Do you use any ion exchange resins or phosphate removers? You might want to reconsider carbon if you are cutting back on skimming to take care of secondary metabolites.

How is your salinity (sodium level specifically) with your balling system? You may have an ionic imbalance of some sort, but the fact that your issues are with LPS I would still guess it's a nutrition issue and not chemical. The amino acids may do the trick. If the problem persists you could take the plunge and try vitamin C (ascorbic acid) dosing.

I've experimented with a few of my LPS and moved them in brighter light and they would show signs of bleaching and when moved back into lower light would color back up. I think the problem is beyond lighting. It's not heavy lighting but it's not dim either; 2 x 250W DE 14K Phoenix run on HQI and two 54W 22K T5s.

Steve what are you using for a skimmer and what size tank and bio-load? Maybe you're not over skimming as much as me, my bio-load is quite small, 5 fish and I also have 3 large clams (not that there necessarily doing much nutrient export). My skimmer is rated for 250-750 gallon aquariums, having a larger skimmer is good but I'm starting to think mine is just too big.

What would you recommend? I was planning on phasing everything in slowly and going from there. Just cutting the skimmer and water changes back may only maintain levels and not restore them but only adding things may not be enough to offset the skimmer if left on. The ultimate goal to me right now seems to be geared to increasing the nutrient level of tank and then attempt to maintain it at a level which provides a healthy balance for all corals in the tank. Should be easy :lol:

You could just de-tune (lower water level & or restrict air intake) your skimmer so it's always on but skimming less.

I like using carbon but I haven't gotten around to building a sump that will really allow for it. I do feel the proper sump would be beneficial and I should move it up the priority list, which will happen soon enough with winter around the corner.

I don't currently use a balling system, it was in the original plan but I'm not set on it yet. I currently just use Kalk and water changes to maintain everything at this point in time. Salinity stays constant as far as I know. I'm definitely going to try the amino and the vitamin C intrigues me so I'll have to look into it.

I would pick the single biggest thing that might bring the turnaround, you think the skimmer is too big, cutting down on running time should have quite a difference, you have run skimmer less before I believe and know what to look for in water parameters, that's likely where I would start.

I read that dry skimming and wet skimming produces similar results and I worry that restricting air flow will decrease the effectiveness and make the chamber too turbulent, you know the whole unstable vs stable protein thing. I'm thinking just reducing the duty cycle will be the most efficient and beneficial way of decreasing the skimming effect.

Well I don't know exactly what to look for in water parameters, should I be aiming for a low concentration of nitrate? Should such levels still be undetectable?

I will start with the skimmer today and maybe just add some amino acids next week. Other things like the phyto maybe a week or two down the road depending on what I use. The water change will probably be a minor change and beside possibly having to dose more Ca and Alk won't result in significant changes in the immediate future.

I haven't tried vitamin C dosing, other than a bit in the food for lateral line disease, but this thread is pretty thorough. http://reefcentral.com/forums/showthread.php?t=1602494

I'm surprised your nitrate and phosphate is zero and your calcium is 400 and alk 8, considering you have so many stony corals and you don't use carbon, phosphate remover, algae or coral harvesting, much in the way of a sand bed, ozone or UV sterilization. You also seem to have modest feeding practices (no phyto, baby brine, or rotifers). Usually coraline algae is a probiotic way of outcompeting nuisance algae, but you have stated that you discourage its growth. You don't have a calcium reactor or a balling system, not even a two-part system. Maybe it's a lot easier to maintain calcium with no coraline algae to compete against.

Your old tank looked like it had the works, and the new one is pretty minimalist. What do you attribute your success to?

Thanks for the link.

I could try different test kits, mine are fairly old (Salifert Nitrate and Elos Phosphate) but they're not expired so I assume they're accurate. I'm always wondering what my clams are doing for me, perhaps I should look more into it.

Yeah my old tank went through about every kind of equipment available and it did get overly complicated in the end even when I tried to simplify things. I contribute my success to stability more than anything and just sticking to the basics. I believe most of what I was doing in the past was not necessarily needed and the goal with my new tank is determine the bare basics and keep things as simple as they need to be. If you have any suggestions I would love to hear them in my build thread, the tank is still a work in progress.

From the tunze 9010 skimmer manual, I copied the following text.

"For operation in surroundings which tolerate a
very low noise level only (living room, bedrooms,
et cetera), the Comline DOC skimmer can be
connected up to a time switch (7). The unit may be
put out of action for eight hours a day, for example.
The missed protein skimming action is caught up
almost after the unit has been switched on again.
The Comline DOC skimmer has the advantageous
property of not changing its setting when switched
off. In this mode of operation, the skimmer should
not be run at the lower limit of the recommended
output for the aquarium."

Might just be propaganda, but it seems to say if you shut the skimmer off for a while (8hrs) then whatever skimming was missed, will be caught up.

I am no expert in water parameters either but there enough people on this board that will give suggestions I am sure, I just don't like the idea of changing too many things at the same time, sometimes they cancel each other out and give false results,

Put it this way, you are trying to find .0005 on a 2" bore to get an RMS of 16, you try different inserts, maybe different coolant or feed rates, but you only change one thing at a time.

Cool thanks, I wish this biology stuff was as simple as the mechanical world, things would definitely be a lot simpler.

Thanks for the info, kinda what I figured.

Just a thought but, I noticed in your pic that you have a relatively large leather mixed in there....I noticed quite an improvement will all my remaining corals after I removed all my leathers (xenia and toadstool) and started running a carbon reactor....I wouldnt think of doing a mixed reef without running carbon to help absorb any toxins that may be being released. Im not positive if the improvement was due to an increase in available nutrients or a decrease in "chemical warfare"

The pic in this thread is a previous setup, I just used it as an example to show healthy LPS in high nutrients. I don't currently have any leather corals or much for soft corals at all. I'm going to start thinking about building a sump soon so I can filter the water properly including carbon.

Oops.....ok never mind then....I'll shut up now:mrgreen:

Haha come one, it's all about the gum ball effect, every bit of insight helps and is appreciated.

It's off and on, sometimes it's foamy and sometimes it's just "fizzing". By fizzing I mean the water level in the skimmer is the same but there is no foam build up in the neck, rather the air bubbles just fizz about an inch or two above the water level. It takes a few weeks to a month to full the collection cup, on my previous setup it would only take a week.

By similar problems do you mean just the fizzing or problems with corals as well?

I just reviewed your tank thread, what kinda water flow do you have in the main tank? I noticed you had a seahorse which I had forgot about.. can they handle high flow or do you have to keep it fairly low for them?

guess what I am trying to figure out is how much water per hour is actualy getting to the sump?

oh and are you running the balling setup yet?

Steve

I have 1000 GPH through the sump, plus two Tunze 6101 power heads which I believe are currently on 30-80% sine waves during the day and 30% constant at night. The seahorse doesn't come out during the day very often, likely because of the higher flow but all flow is shut off during feeding so the seahorse doesn't have any issues eating and the flow cuts back in the evening so the seahorse gets a couple hours of light and low flow to swim around. He seems well adapted to the system.

No balling yet, just water changes and a little Kalk seems to do fine for now.

I had zero growth out of softies and LPS, SPS had slow growth. Skimmer would just sit there and fizz. I dropped my skimmer down to one pump and everything seemed to be improving when I lost my light timer while on holidays and the tank went without light for a few weeks. So I'm unable to confirm whether the improvement would have continued.

The 90 gallon was very low tech, maintained with skimmer and water changes only,plus a tad bit of cal. dosing

Well I have an update but it's not good :sad:

All I changed was the skimmer which was set to a 0.5 duty cycle (12am to 12pm). Sunday night was fine and no problems where presented but last night proved different. I never checked the tank this morning so I'm not sure when this went down but I can home from work today to find that the skimmer had overflowed, it was off by the time I got home but the sump was still foamy and the skimmer cup was full of clear water. I emptied the collection cup Sunday and virtually nothing was in the skimmer on Monday so I don't think a lot of skimmate was dumped in the tank.

The bad part of this story is that virtually all my fish are dead, including my seahorse and lionfish which I've had for close to 20 months. All corals, clams and other inverts seem the same. Overall the tank looks normal, I'm going to test amonia and nitrite right away but I'm guessing these will be normal.

Skimmer is back on regular full duty cycle but I'm completely clueless what happened. This is likely the last straw for me and this hobby at this time, obviously I don't have the proper time and patience to spend on it right now and I just can't handle the extra stress. More than likely everything will be up for sale soon enough but if you have any ideas on what happened please still share them because I would still like to know.

I have no answer as to what happened, it is however an engineering thing and I am sure you will both figure it out and not give up.

Hang in there.