Alkalinity Low and Calcium normal using Kalk Reactor

[DopeCantWin]

My Alkalinity is around 7, while the Calcium is 440. The Magnesium is 1500+. The tank is a 90 with a lot of SPS. The top off is going through a Kalk Reactor. I was thinking a Calcium Reactor, but that would raise both. Should I just start dosing baking soda+water or do I have any other options?

 

[BlueDartReefer]

While I prefer my Alk level to be in the 8-10 range, both your Alk and Ca levels fall within normal parameters. I might suggest adding vinegar to supersaturate your Kalk, but I am not sure how feasible that is with a reactor.

 

[kgross]

It sounds like your kalk is not quite keeping up. Remember for every 2.8 dkh of alk, your calcium will only raise 20 ppm. So even if your kalk raised your alk up to 10, your calcium would only be at 460, which is within the error of your test kit.

So I would highly suggest if you boost your alk, use a balanced 2 part and dose both the alk and calcium parts.

 

[bertoni]

I agree that using a 2-part is the safest choice over the long haul. It's fine to dose only alkalinity for a bit if you want to lower the calcium level, though.

 

[DopeCantWin]

I've tried to do 2 part in the past, and I just kept screwing it up. Might have been because I wasn't using exact enough pumps. I was using Tom's Lifters on a controller.

 

[bertoni]

I agree that you need a very accurate pump if you want to auto-dose.

 

[Randy Holmes-Farley]

If it were my tank, I'd use limewater and a two part, but limewater and a CaCO3/CO2 reactor can be a fine choice.

 

[DopeCantWin]

I had my water tested at two LFSs and they both told me my calcium is actually 500, not the 440 I tested today with Salifert. So my plan is to dial back the Kalk reactor because it is putting out too much and the Calcium is pushing down my Alkalinity(8dKh). I might start another thread about the Salifert test being wrong.

 

[bertoni]

Calcium at 500 ppm won't affect alkalinity to any interesting degree. Lots of people run higher than that with no issues. The LFS results might be more accurate, might not. I think both numbers are close enough for our purposes.

 

[Randy Holmes-Farley]

I agree.

Also, dialing back the limewater will only make the alkalinity decline more, and the effect on calcium will not be easily noticed. For each 20 ppm decline in calcium from reduced limewater, alkalinity will necessarily decline by 2.8 dKH.

If you want alk higher and calcium lower, just give alkalinity a boost with some baking soda each day until the alk stays where you want (probably means daily dosing of baking soda) and calcium slowly declines (unless water changes with a high calcium mix keep pushing it up).

 

[DopeCantWin]

I use Reef Crystals, so extra low on the Calcium. I've lowered the limewater by a little. I was hoping to do that anyway because it was putting too much water in the tank. I'll be monitoring the tank daily for Alkalinity changes for a while. Maybe put in a teaspoon of baking soda a day (100 gallon volume, raising the dKh by .2) until I can figure out the rate at which the Alk is dropping. At which point I'll set up some kind of automated dosing. Any gaping holes I've overlooked?

 

[karsseboom]

Well simply put. Your tank uses more alk then it does cal. The kalk adds both in a balanced porporations. The cal reactor will not add more cal then alk, it also add cal and alk in a balanced porporations. Your gonna have to add some alk by hand in order to keep up the your tanks alk demand while using kalk.

 

[Randy Holmes-Farley]

Actually, I'd word it that the Reef Crystals is putting in slightly excessive calcium relative to its alkalinity, and so as both decline proportionally, alk seems to be depleting faster and hits a bottom first, but it is the salt mix that is skewing things, not disporportionate use in the tank.

 

[DopeCantWin]

Actually, I'd word it that the Reef Crystals is putting in slightly excessive calcium relative to its alkalinity, and so as both decline proportionally, alk seems to be depleting faster and hits a bottom first, but it is the salt mix that is skewing things, not disporportionate use in the tank.

Technically until a few days ago I hadn't done a water change in maybe 6 months. I did a 13 gallon change. But other than that, I could throw in a teaspoon of baking soda during a change.

 

[Randy Holmes-Farley]

Still, if you started with Reef Crystals (according to Billy, that is 490 ppm calcium and 13 dKH) and allowed CaCO3 use to take up calcium and alkalinity, then you could end up at 440 ppm calcium and 6 dKH even with exactly proportionate demand.

 

[tmz]

I used limewater for top off from a still reservoir an a CaCO3 reactor together for a few years. I prefer and now use just limewater with an occasional addition of a relatively small amount of baked baking soda as well as regular water changes. I don't need the extra calcium from the calcium reactor or the lower ph or any impurities in the media.