Low Alk! Can't get it to increase

[WallysWorld]

I have a Reefer 170 that is two months old. Started with live aragonite sand, about 1.5 inches deep, and dry reef saver rock, 30 lbs. Very lightly loaded - two small clowns, and 4 small frags (3 zoas, one kenya tree). I did lose one zoa immediately after putting it in the tank, and have removed it, about 2 weeks ago.

Initially I was testing with Red Sea KH tester(not the Pro version), and had values of 8-9 dKH. About 2-3 weeks ago switched to Hanna Checker H1772 with direct readout in dKH. I was tired of counting drops.

My Alk on the Hanna Checker since I started using it been in the 6.7-7.1 dKH range. Here are the rest of my tank parameters from most recent test:
Temp: 81.2°F
Salinity: 36 ppt
Ph: 8.2
Nitrate: 0-2 ppm
P04: 0.05 ppm
Ca: 450 ppm
Mg: 1600 ppm

I'm manually dosing 25ml of Red Sea Foundation B every night. Which should result in the maximum recommended daily increase of 1.4 dKH. Alk does initially increase, but over 24 hours drops back to the range cited above. I test at about the same time every night.

I was dosing NoPox when I started the tank, but tapered it down and have not dosed any in the last week. I'm monitoring Nitrate and PO4 in mean time.

I'm trying to follow the Red Sea Mixed Reef recipe and get my Alk to 11.5 dKH. I'm a little concerned about my high Mg as well, lowest measurement for Mg was 1460 ppm.

What should I do?

 

[Randy Holmes-Farley Verified Community Expert]

11.5 dKh is pretty high. The higher you want to maintain it, the more you will have to add every day since demand rises as the alk rises.

1.4 dKH cannot be the max daily increase (no matter what they say). Many tanks use more than that every day, even soft coral tanks. Just add more of both the calcium and alkalinity parts.

Ignore magnesium now. it is fine.

 

[WallysWorld]

Thanks!

I'm now chasing down several of your articles on Alk and Calcium.....I've got some night time reading ahead of me.

 

[WallysWorld]

11.5 dKh is pretty high. The higher you want to maintain it, the more you will have to add every day since demand rises as the alk rises.

1.4 dKH cannot be the max daily increase (no matter what they say). Many tanks use more than that every day, even soft coral tanks. Just add more of both the calcium and alkalinity parts.

Ignore magnesium now. it is fine.

I'm still struggling with ALK.

I upped my dose of Red Sea Foundation B to 35ml daily, dosed as a single time at night after ALK testing. Over the two week period the average test value was 7.1 dKH with a range of 6.7 to 8.4 dKH. After consulting with my LFS given the coral load (5 small frags), and the salt mix I'm using (Red Sea Coral Pro, black bucket which is supposed to mix to ~11 dKH), decided to stop dosing altogether and rely on water changes.

No dosing ALK of Ca for two weeks. I've done two 13% water changes as standard maintenance. Here are current tank values:
Salinity 35 ppt
Ph 8.2
Alk 4.6 dKH
Ca 370 ppm
Mg 1360 ppm

What would you recommend?

 

[Reefahholic]

Man, that is just weird. Are you sure you’re testing correctly? What test kits are you using.

I know tell you that with that brand of salt you are using and the minimal corals you have- something is not right.

Have you checked with a Hanna ALK tester. You should be 11 DKH all day. Hmm.....

 

[WallysWorld]

Man, that is just weird. Are you sure you’re testing correctly? What test kits are you using.

I know tell you that with that brand of salt you are using and the minimal corals you have- something is not right.

Have you checked with a Hanna ALK tester. You should be 11 DKH all day. Hmm.....

I'm reasonably confident with my testing. Primarily using the Hanna Alk Checker, but I've also spot checked it with the Red Sea Alk test that was part of the Marine Care Test Kit. Both test results agree with each other to the resolution of the Red Sea Test (0.5 dKH). Was thinking of purchasing one of those Triton ICP-OES test kits - but its expensive, and I'm not certain it would tell me more than what existing tests already tell me.

Could my RO/DI water be the cause, I don't have a TDS meter? Its about the only thing I don't test for, thinking it is a relatively small risk. I do get a small amount precipitation on the heater and powerhead in the brute bucket I use to mix saltwater, if I leave it to mix overnight. I haven't tested Alk in freshly mixed saltwater, but thinking maybe I should.

 

[rkpetersen]

With that setup, you must have a lot of abiotic precipitation of calcium carbonate happening somewhere. Do you see any crusty white precipitate on the floor or walls of your sump? Or even on the glass of your DT? Any hard clumped areas in your sandbed? One suggestion - Resume dosing, but switch to smaller divided doses rather than one massive daily dose. I didn't solve my issue until I put the 2 part on an automatic doser, but by that point I was also adding a lot of corals including fast growers like montis (you shouldn't really need a doser yet).

 

[rkpetersen]

I do get a small amount precipitation on the heater and powerhead in the brute bucket I use to mix saltwater, if I leave it to mix overnight. I haven't tested Alk in freshly mixed saltwater, but thinking maybe I should.

Oh, this is a concern for sure. Coral Pro is meant to be used within a couple hours of mixing, and no more than 4 hours. It also shouldn't be heated during mixing. I would guess that the precipitation you're seeing in the brute is actually a large part of the calcium carbonate that was initially dissolved. Definitely test your salt water for alk 30 minutes after mixing, and then after heating and mixing overnight; I bet you'll be shocked at the drop.

 

[WallysWorld]

Oh, this is a concern for sure. Coral Pro is meant to be used within a couple hours of mixing, and no more than 4 hours. It also shouldn't be heated during mixing. I would guess that the precipitation you're seeing in the brute is actually a large part of the calcium carbonate that was initially dissolved. Definitely test your salt water for alk 30 minutes after mixing, and then after heating and mixing overnight; I bet you'll be shocked at the drop.

Thanks. Sounds like more testing.....

Noticed you're in Seattle. What part? I'm up north in Edmonds.

 

[rkpetersen]

Thanks. Sounds like more testing.....

Noticed you're in Seattle. What part? I'm up north in Edmonds.

Eastside. But for anyone who doesn't live around here, it's 'Seattle'.

 

[Dennis McGrath]

How much are you topping off each day with RODI? Mine would lower with the water top off until I mixed it with Seachem Reef Buffer.

 

[Reefahholic]

I'm reasonably confident with my testing. Primarily using the Hanna Alk Checker, but I've also spot checked it with the Red Sea Alk test that was part of the Marine Care Test Kit. Both test results agree with each other to the resolution of the Red Sea Test (0.5 dKH). Was thinking of purchasing one of those Triton ICP-OES test kits - but its expensive, and I'm not certain it would tell me more than what existing tests already tell me.

Could my RO/DI water be the cause, I don't have a TDS meter? Its about the only thing I don't test for, thinking it is a relatively small risk. I do get a small amount precipitation on the heater and powerhead in the brute bucket I use to mix saltwater, if I leave it to mix overnight. I haven't tested Alk in freshly mixed saltwater, but thinking maybe I should.

Definitely test your water source. Also, test your freshly mixed SW. Something is way way off.

 

[Reefahholic]

One of Red Sea’s chiefs said mix at lower temperatures. After that then you can heat the water. Let me find the video. I’ll link it up.

Oh, this is a concern for sure. Coral Pro is meant to be used within a couple hours of mixing, and no more than 4 hours. It also shouldn't be heated during mixing. I would guess that the precipitation you're seeing in the brute is actually a large part of the calcium carbonate that was initially dissolved. Definitely test your salt water for alk 30 minutes after mixing, and then after heating and mixing overnight; I bet you'll be shocked at the drop.

 

[Reefahholic]

Here’s the video I was taking about:

 

[rkpetersen]

One of Red Sea’s chiefs said mix at lower temperatures. After that then you can heat the water. Let me find the video. I’ll link it up.

Yes, same here:


https://5w56d28u4co20frgwagf5y18-wp...guage-Manual_GB_FR_DE_IT_ES_PT_JP_CH_v17a.pdf

 

[WallysWorld]

I did a water change on Sunday. I checked the Alk of the newly mixed water. Spot on according to the parameters on the salt bucket - 11.0 dKH, tested ~1 hour later after raising temp to match tank - 10.9 dKH - good! I used the salt as soon as it reached temperature.

Tank is 40 gallons, Alk was 6.4 dKH prior to change, changed 5 gallons. 24 hours after change Alk of tank is 6.3 dKH (pH 8.2, Ca 375 ppm, Mg 1440 ppm)! Wish I knew what was consuming my Alk!

I'm going to dose 10ml of Foundation B (Alk buffer), Foundation A (Ca), three times a day for a while to see what happens. 30 ml is the amount on the bottle labels that should result in ~8 dKH Alk and 450 ppm Ca. This will be a bit of a pain, as I'm dosing manually.

Anyone with idea what's going on? Thoughts on my methods?

 

[WallysWorld]

I did a water change on Sunday. I checked the Alk of the newly mixed water. Spot on according to the parameters on the salt bucket - 11.0 dKH, tested ~1 hour later after raising temp to match tank - 10.9 dKH - good! I used the salt as soon as it reached temperature.

Tank is 40 gallons, Alk was 6.4 dKH prior to change, changed 5 gallons. 24 hours after change Alk of tank is 6.3 dKH (pH 8.2, Ca 375 ppm, Mg 1440 ppm)! Wish I knew what was consuming my Alk!

I'm going to dose 10ml of Foundation B (Alk buffer), Foundation A (Ca), three times a day for a while to see what happens. 30 ml is the amount on the bottle labels that should result in ~8 dKH Alk and 450 ppm Ca. This will be a bit of a pain, as I'm dosing manually.

Anyone with idea what's going on? Thoughts on my methods?

Forgot to mention, I got a good look inside of my return nozzle. It has a nice coating of white powder, so I'm guessing that's one location where its precipitating.

 

[lapin]

I dont know about the fancy foundation stuff. When I needed to raise mine I used Randys recipe for baked baking soda mixed with water. Worked until I was able to get my calcium reactor going. That made ph, cal and alk stable.
http://reefkeeping.com/issues/2006-02/rhf/
Im going to say that in my opinion if your tank is new you have stuff growing in the rocks and sand bed that is eating up your alk.

 

[rkpetersen]

I did a water change on Sunday. I checked the Alk of the newly mixed water. Spot on according to the parameters on the salt bucket - 11.0 dKH, tested ~1 hour later after raising temp to match tank - 10.9 dKH - good! I used the salt as soon as it reached temperature.

Tank is 40 gallons, Alk was 6.4 dKH prior to change, changed 5 gallons. 24 hours after change Alk of tank is 6.3 dKH (pH 8.2, Ca 375 ppm, Mg 1440 ppm)! Wish I knew what was consuming my Alk!

With those parameters, the most you could hope for would be a rise of alk to 6.9, and that's assuming no consumption at all over that 24 hours. That still doesn't explain the additional drop, though.

I've had problems with alk in the past as well. I believe the amazing vanishing alk act has puzzled many others as well. The apparent only explanation is abiotic precipitation. I say apparent, because I used to think that possibly CO2 was leaving the water into the air, and the carbonate (alk) level then dropping to re-equilibrate with dissolved CO2. Although I'm honestly still not convinced that something like this doesn't happen, I've been told by experts that this doesn't occur and that alk levels can't change in this way. So there's that. And it sounds like you do have some abiotic precipitation; I suspect that if we can actually see it, a lot more is leaving the water than we realize.

 

[rkpetersen]

Im going to say that in my opinion if your tank is new you have stuff growing in the rocks and sand bed that is eating up your alk.

To play devil's advocate, what would be using up carbonate like that in a new tank? Stony corals, tridacna clams, coralline algae - What else incorporates a significant amount of carbonate as it grows?