Levels fluctuating
 

I'm having some issues with my reef and it's causing me to loose sps on my 300 gallon system. My alk levels seem to fluctuate quite a bit. Mag is at 1320, cal at 420 and alk at 8. I'm dosing with a dosing pump 220ml of calcium and alk daily. I test mag and calcium weekly and they are constant but my alk remains constant some days, other days it doesn't get costumed so it shoots up my alk .5dkh if I don't catch it, within a few days it can crawl up and cause damage on my carbon dosed system.

I also recalibrated the doser to make sure it wasn't the problem. I'm using salifert test kits and the tank is almost 1 years old.

Any ideas?

Did you try to check if the line is ok... I noticed in my system that the alk was getting lower and lower, try to calibrate the pumps and everything looked ok, till I noticed that one of my line was obstructed and since I put a new one in seems fine


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Alkalinity doesn't really fluctuate like that without everything else fluctuating (which would point to salinity fluctuating).

What span of time is there between your testing? When you test the alkalinity high, what do you do to fix it?

I checked the line and everything seems fine.
It can't also be salinity, I got an ATO that kicks in as soon as about a litres of water evaporates.

I wonder if one of my test kits have gone bad and it's giving me bad readings. Can it be caused by calcium or mag actually being too low? My alk kit is faily new and i compared the alk to my old kit and it's only .3dkh difference. The mag is a brand new kit but the calcium is needing replacement soon but still within expiry.

I've been testing alk every night at the same time. When it doesn't get consumed, I unplug the alk and calcium hoses from the doser because i dont want it to get out of balance until the next night or the night after until it drops back to 8. The calcium probably does fluctuate, but it would only be 4ppm so it's kind of hard to measure that on a daily basis.

well i personally won't put that theory to rest.
i tested water regularly but recently switched all my products over to aquaforest product (probiotic salt and their balling method) and wanted to test a little more rigorously so i bought new test kits. against my old salifert test and using the same water sample i'm getting readings of 430 calcium 8.6 kH from my old kits to 500 calcium and 11.8 kH from the new. my corals and livestock look improved at the moment so i'm not going to adjust but it's tough to trust such variance especially when the colors don't appear equal.

That's quite a difference in test readings!!! Are the new ones also salifert?

yes it was another salifert test and the results are higher across the board with Cal,kH and Mg.

Why not try lowering your alk dose....

I test my alk with Hanna vs salifert and the difference can be about .4-7 on the salifert.

But let's say if your alk is at 8 and your dosing 220 ml per day and it's rising why not first try to adjust your doser 6 points belowso 210ml or 214ml per day and see if it stabilizes out. I think salifert is abit higher readings than the Hanna but this could only be for me...

I am by far and away no expert, however I have run a 500 gallon system and if that has taught me anything it's that huge volume system perams are a lot like stopping a fully loaded freighter.........it's a long and painful process. If I were a gambling man I would hedge my bets on testing. I would also stash the salifert kits for back up testing Alk and PO4 and run Hanna. I keep test kits of each on hand just in case as a back up test to check reagent and the likes if I get odd readings, but unless you have a veritable forest of SPS your perams should not swing that badly. Calcium and Mag won't swing too terribly far unless you have the forest of SPS either.
That and you would benefit immensely from a reactor with a system that big. Good luck

Ok, then it sounds like you need to adjust your doser a bit lower. Which products are you using for dosing?

You make a very good point about the freightliner lol. I pulled out my hanna alk kit and it happened to have a little reagent left so i tested it against my salifert and it gave me the exact reading.

I'm using baking soda for alk, aquaforest calcium and magnesium. I'm also dosing their trace elements but that's shouldn't have any impact on this issue. I could adjust it to be a bit lower, but shouldn't the tank still consume alk daily?

I think this problem started about a month ago when I switched my lighting system from all t5 to half t5 half led.I understand corals take time to adjust but some days consuming elements and others not just seems strange.

::::UPDATE:::::

this morning I added 10 tsp of calcium chloride anhydrous to bump up my calcium (thinking maybe the calcium kit being older was giving me a bad reading). That should have brought my calcium to 435ppm.

Actual results tonight
Alk 9 (up 1 dkh without adding any)
Cal 470 way higher than I dosed
Mag 1430 (up 110ppm and i didn't dose any)

:laluot_08:

While ca is not bad to bump up quickly, I think long term you gotta figure out what your tank consumes weekly then adjust accordingly. I admit when I was setting up my doser Param's bounced quite abit as ca was low and same as mg,
But once my alk stabilized I've been testing weekly and it's rock solid for months.

I had lots of po4 built up in my tank which slowed the growth of sps and coraline, this played a big impact on how much of the big 3 gets consumed especially alk. Our tanks is a constant adjustment, this is what makes it fun. If there was nothing to tinker with one could get bored....

If you're testing a lot you must be going through test kits. Like Gary said if you can afford to or see one come up Fs in your area get the Hanna for phosporous and alk, I find them to be a lot more accurate.

Do you use a measuring cup or digital scale to measure the bulk Chems?

I actually have all the hanna testers. Alk cal 2 different phosphate testers but i just find the salifert a little quicker to use but hanna is probably a lot more accurate.
I make all the different chems using a a digital scale.

I'm looking into a calcium reactor, that might make this a lit easier to balance out. Probably doesn't help that my doser is a Jebao that gets jammed up every couple months.

Thanks everyone for all the help :biggrin:

You should use Sodium bicarbonate for alk

I am using a jebao aswell and it never jams up on me, although I make my own mixing measurements and not off the brs website. Roughly 8 tbsp sodium bicarbonate to 2.5 liters of water.

Sodium bicarbonate is awesome to use as alittle amount can bump your alk up, only downside is ph rises quickly too!

I doubt it's a test kit issue if your using quality kits. Titration method testing is more accurate for Ca, Alk and Mag then the digital colorimeter tests. Info direct from Lamotte technical support.

My suspicion is it could be related to carbon dioxide levels in the house and consequently in the tank. How does your pH fluctuate during a day? Monitor it over a week long period, say every 3 or 4 hours. There may be a correlation between co2 levels in the tank(lower pH) and the alk issue. ie High co2 would cause the alk to be depleted in the tank.

Cheers,
Tim

Sodium Carbonate is what has a significant effect on PH sodium bicarbonate has little effect on PH.

I prefer to use sodium carbonate (soda ash) as I suffer from low PH.

That is a very valid point regarding the relationship between CO₂ and alkalinity – see link below that illustrates this very well.
http://www.reefkeeping.com/issues/2004-09/rhf/

Before you toss your doser and head for a calcium reactor, have you ever calibrated your doser or checked the consistency of each dose? In any case, at 200+ ml of alkalinity and calcium solution a day I'd say you're definitely in the range where a calcium reactor will be more economical in the long term – and as others mentioned, it will keep your values ever so slightly more consistent.

Hey guys, just back for an update. I stopped dosing calcium for a few days and just dosed alk until the levels dropped to cal 430, kh 8. In the meantime I picked up a calcium reactor and put it in. My levels have perfectly stable since then.

Thank you for all the help!!!

Awesome thanks for the update!