Thoughts on over skimming

[mr.wilson]

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.

[sphelps]

Originally Posted by mr.wilson

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?

[mr.wilson]

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.

[sphelps]

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.

[mr.wilson]

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.

[sphelps]

Originally Posted by mr.wilson

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 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 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.

[golf nut]

Originally Posted by sphelps

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.

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?

[mr.wilson]

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.