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