Low Alk and High Calcium - how to correct

WallysWorld · Apr 12, 2020

My Alk is low and Calcium is high. What should I do to correct this? Is it as simple as changing the dosing amount on my pump? I have been dosing Red Sea A, B, and C on separate pumps in the following quantities for at least 7-8 months with no changes:

Red Sea KH/Alk 11 ml/day
Red Sea Ca+ 5 ml/day
Red Sea Mg 2 ml/day
Red Sea NO-POx 3 ml/day

All dosed several times per 24 hour period (above are total daily amounts)

My tank is 37 gallons, I've had it running for 2 years, and it has been very stable until recently, say the last month or so. Alk has been around 7 dKH and calcium around 450ppm. I'm also curious as to what possibly has changed.

Parameters from todays measurement:
Temp: 78.2F
Salinity: 35 ppt
Ph: 7.77
Alk 3.7 dKH
Calcium: 500+ppm (this is the top of the scale on the RS Test Kit - it was within a drop or two of changing color)
Magnesium: 1300 ppm
Nitrate: 1ppm
Phosphate 0.07 ppm

Thanks in advance for advice

redfishbluefish · Apr 12, 2020

I've never seen alk that low.....and am wondering if it is even possible. What test kits are you using? The first thing I'd do is verify testing by either having a friend use their kits or taking a sample to your LFS. If those numbers are real (or if calc is real), I'd stop dosing calc all together until the number drops.

If you don't have a reefer friend to test or the LFS isn't that close, test newly made saltwater and see if your test results match what the salt says it should be.

homer1475 · Apr 12, 2020

I'm thinking testing error?

I don't even think an ALK that low is even possible?

What are you using for test kits?

WallysWorld · Apr 12, 2020

I tested Alk three times with two different methods. I used a Hanna tester twice and double checked it with a Red Sea titration kit. The Hanna numbers are consistent. The Red Sea kit was in the 4-4.5 dKH range.

I know this is really weird.

Thanks

Randy Holmes-Farley · Apr 12, 2020

WallysWorld said:
I tested Alk three times with two different methods. I used a Hanna tester twice and double checked it with a Red Sea titration kit. The Hanna numbers are consistent. The Red Sea kit was in the 4-4.5 dKH range.

I know this is really weird.

Thanks

Try the kit on some new salt water before boosting the tank that much.

And be sure it is not in units of meq/L, but really is dKH.

WallysWorld · Apr 13, 2020

Randy Holmes-Farley said:
Try the kit on some new salt water before boosting the tank that much.

And be sure it is not in units of meq/L, but really is dKH.

I tested a newly mixed batch of salt water (Tropic Marin Reef Pro Salt), and result was 7.9 dKH. Then did another test of the tank water and result is 3.9 dKH.

Do I simply increase the dosing of the Red Sea Alk? Or should I be doing something else?

Any thoughts as to what is causing the Alk to be so low?

WallysWorld · Apr 13, 2020

I feel like an idiot! Decided to check the calibration on the dosing pump. In the process noticed that two of the pumps had Foundation A (Calcium) bottles connected to them. Should have been one Foundation A and one Foundation B (KH/Alk).

So now I know why the Ca was so high and the Alk so low!

I'm going to stop dosing Ca and let it fall naturally to a normal number. Any advice on raising Alk?

Should have checked the pump and reservoirs earlier!

Martin Kuhn · Apr 13, 2020

That explains it

besides continuing to add Alk in the dose you had previously. I would recommend to raise Alk Fast. I would aim for additionally +2dKH per day the next days.

and of course immediately Stop dosing Ca until it lowered around 430ish by tanks consumption.

Albertan22 · Apr 13, 2020

I strongly recommend against following the above recommendation. I would never increase alk by 2 dkh or more a day. Bring it back slowly or you will burn all your coral and could end up with a huge ph swing doing even more damage. I’d bring it up slowly, maybe 30-50% of your normal daily maintenance dosing rate until it’s back to normal. Test frequently and watch the tank closely to see how it reacts.

Martin Kuhn · Apr 13, 2020

I would agree to what you say for nearly all other parameters but Alk.

It is not only my believe that it is better to increase dKH fast in this critical low dKH range. In case you think this might harm your animals. Split the +2dKH dose in several chunks.

in case you are concerned about the ph (.... I wouldn’t) you can take soda ash (Na2CO3)

homer1475 · Apr 13, 2020

I'm not even sure what I would do in this situation.

On one hand you have severely low ALK that needs to be raised to at least natural salt water levels in a hurry, but have been told, and read many times over to never increase ALK by more then 1dkh a day.

On the other you still have severely low ALK and someones suggesting to bring it up by 2 times the normal daily DKH swing.

I would at the very least if it were me, probably go up to 5DKH(1.3DKH) in one shot, then slowly raise it to 7(or whatever you would like it to be, but go slowly) over the course of a couple days(never more then 1DKH/24H). I would certainly stop CAL additions until you start to see it fall to normal, then go back to auto dosing.

Homebrewer · Apr 13, 2020

The tank is 37 G, my suggestion would be to do small(ish) water changes every few days, or really small changes daily. The new water should be correctly balanced and after a few changes, parameters should start to even out.

If this were a large volume then maybe you’d have to approach it differently, and I know there are economic arguments to be made here, but water changes would seem to be to be the most straightforward way to get to balance without causing a dangerous swing.

Just my $0.02.

Rmckoy · Apr 13, 2020

is 3ml nopox per day too much for 37gal ?

I believe dosing it does have some effect on alk and cal ( typically alk is higher after nitrate levels lower . )

Homebrewer · Apr 13, 2020

I think your issue is solely due to the double-dosing of calcium and the lack of alk. If it were me, I’d get those back on track via water changes as I described. If you go that route, you can likely cease dosing during this period altogether, including NO3-PO4X. Your nitrates and phosphates likely won’t be an issue if you are doing small, perhaps daily water changes in a tank that volume.

I’ve never used NO3-PO4X. I’ve used a similar carbon-dosing product from Prodibio, but it isn’t specific like the Red Sea product. Nevertheless, you could try do dose your way out of this with alk, but then if you keep dosing everything else, then you’re just adding variables that you don’t need to deal with right now.

Again, just my $0.02 here, but I think water changes will get you back to where you want to be, then you can reassess and decide what/how to dose from there, once you’re back on track.

SliceGolfer · Apr 13, 2020

It’s good you identified the issue. Getting your parameters in check slowly is great advice. Either through small water changes or dosing Alk no more than .5ppm to 1ppm DKH daily. Calcium would balance out over time in either case. As @Randy Holmes-Farley has stated many times, it takes up to 2ppm DKH to deplete 20-40ppm calcium.

Whichever path you choose, I advise against this suggestion:

Martin Kuhn said:
besides continuing to add Alk in the dose you had previously. I would recommend to raise Alk Fast. I would aim for additionally +2dKH per day the next days. And of course immediately stop dosing Ca until it lowered around 430ish by tanks consumption.

WallysWorld · Apr 17, 2020

I did a 10% water change, and have been dosing Alk for 3 days now. I've been testing Alk daily, and so far I've seen no detectable change in Alk - still hovering around 4 dKH. Freshly mixed water tests a 8 dKH, so I'm confident with my testing.

My Dosing pump is programmed for 18ml/day spread over 8 equally spaced doses. 18 ml should be +1.4 dKH for my volume according to calculator, I've also randomly had it pump 5 ml extra each day. Doing a 20% water change later today.

Should I be concerned that Alk isn't increasing? Is there anything else I should be doing?

biom · Apr 17, 2020

It is possible there is precipitation caused by imbalance between calcium, magnesium and alkalinity. I would do more water changes

Randy Holmes-Farley · Apr 17, 2020

biom said:
It is possible there is precipitation caused by imbalance between calcium, magnesium and alkalinity. I would do more water changes

he reports calcium at about 500 ppm and magnesium at 1300 ppm. I don't see a problem.

Randy Holmes-Farley · Apr 17, 2020

WallysWorld said:
I did a 10% water change, and have been dosing Alk for 3 days now. I've been testing Alk daily, and so far I've seen no detectable change in Alk - still hovering around 4 dKH. Freshly mixed water tests a 8 dKH, so I'm confident with my testing.

My Dosing pump is programmed for 18ml/day spread over 8 equally spaced doses. 18 ml should be +1.4 dKH for my volume according to calculator, I've also randomly had it pump 5 ml extra each day. Doing a 20% water change later today.

Should I be concerned that Alk isn't increasing? Is there anything else I should be doing?

1.4 dKH per day is not that much. I'm still not convinced the test is accurate, but assuming it is, I'd add more as baking soda/sodium bicarbonate.