Exhausted with Low PH!

[Ann Enomy]

First post here but a 5+ year veteran to reefing. Let me start by saying that my PH probe is calibrated and overall the system is stable, I just cannot get PH over 7.9. I know there are many that say don’t worry about it however I suspect that this is the reason that I am not able to keep any stony corals long term (3+ years). They stay in my tank, look ok, accept food but just do not grow and eventually die. Soft corals, Zoas, shrooms, Anenomes and gorgonians thrive.
The tank is in my medical office so I suspect CO² is an issue but do not have operating window or option to feed skimmer fresh air. I have tried to use a CO² scrubber and when using can hit 8.0-8.1 for the first 2-3 days but then drop again. The cost seems prohibitive. I have tried to dose kalkwasser in the makeup water which gets the PH up but then Calcium and alkalinity gets way too high(650+, 11+ respectively). Any other ideas are welcome. Also I am questioning the recirculating skimmer. The longer dwell time helps get the junk out but does it have less of an aeration effect? would I be better going with a standard pass through?
My system:
120gallon with 40 gallon sump, Rollermat, Reef Octo classic 200ext recirculating skimmer with 130GPH feed rate(per apex fluid monitor), Clearwater CW-100 Algea turf scrubber ( 16 hr opposite light schedule). Carbon reactor, Cermedia large block and 4 quarts of balls, BRS 2 part, Carbon Dosing (60ml vinegar daily dosed on the hour automatically).

My parameters: all taken from average over 3 months as recorded by APEX. I test weekly. I have done ICP testing and everything fell in the “green"
PH 7.7-7.9 daily fluctuation
Alk 8.96
Ca 50O
MG 1500
Nitrate 4
PO4 .035
Salt. 35

My Habits:
5 gallon water change 4x per week, I vacuum the gravel each time
Scrape ATS every other week
Change carbon monthly
Test Alk, Ca, Mg No3 and PO4 weekly

 

[Larry L]

I have tried to dose kalkwasser in the makeup water which gets the PH up but then Calcium and alkalinity gets way too high(650+, 11+ respectively).

Just checking, when you say "make up water", do you mean water change water, or evaporation top off water? I'm assuming evaporation top off...

Kalkwasser is probably still your best bet for getting the pH up. Since your Ca and Alk got too high you could always try mixing less kalk into your top off water, but that's hard to regulate, and evaporation rates can vary too. The best way is to set up a separate doser for the kalkwasser so that you can dose exactly what you need to keep Ca and Alk where you want them, and then rely on your top off to make up the difference for evaporation (which in your case should work because the amount of kalkwasser you need is obviously less than what you need for top off).

 

[Larry L]

5 gallon water change 4x per week, I vacuum the gravel each time

Wow, I'm impressed - you must have a lot of free time. ;-)

 

[doodledreads]

Give macro algae scrubbers a try? since it is enclosed, theory is that it will consume the co2 from the water, not sure how true it is. For me, running a airline from outside to skimmer helped. That and stopping carbon dosing, dosing my alk during the night over several hours.

 

[Ann Enomy]

Wow, I'm impressed - you must have a lot of free time. ;-)

Honestly I have it down to almost no time. Grab 5 gallons from the mixing barrel, throw the ATO pump in the 5 gal bucket with new SW, start vacuuming to fill another 5 gal bucket, throw ATO pump back in reservoir, Done. I do it during lunch and it takes less than 10 min.

 

[Ann Enomy]

I did notice a mistake in OP, NO3 is not 4 it's .4. Also I should have mentioned I have read Randy’s article about low PH. If I aerate tank water in the room the PH will raise by 0.08 and if outside then 0.13. Problem is no way to get fresh air without making holes in roof or wall which is not an option (lease the office suite). Do you think this .08 increase is worth getting a pass through skimmer for? I doubt an airstone in the sump would be enough, correct?

 

[Devisissy]

Had the same issue. 7.8-7.9 with kalk, about one tablespoon in my 5 gallon ATO. I added chaeto in a reactor with leds on 24/7 and got it up to 8.2, but the chaeto didn't stay alive and it was a pain to always have to replace so I went back to having low PH at 7.8-7.9.

Then last year we converted the house to Gas and central air. Before it was baseboard and window AC's. Now I am at 8.2 always. I think since the furnace and AC vents to the outside and there is a ton of air movement compared to before that solved my problem. I don't know it any of this helps you or not, but chaeto worked for me and kalk for sure worked for me. But just getting a furnace was the real fix.

 

[Ann Enomy]

I do have a algae turf scrubber which I would assume does the same as cheato. Unfortunately I can’t change structure so fresh air is not an option

 

[BayouReefer]

I may be wrong but I believe that the highest concentrations of CO2 come from closest to the floor can you extend the air intake for your skimmer to see if that helps

 

[Silent]

You said when you used kalk your other number went very high. If thats the case you would need to reduce your dosing regimen. If you do that you can keep the correct parameters and keep ph high.

 

[Retro Reefer]

I wouldn’t worry about it, mine will sometimes peak about 8.09 but mostly stays in the high 7’s with 7.9 probably being a average.. my corals are growing like crazy.

 

[Roy Arena]

I might start with stopping the carbon dosing. Vinegar does impact or lower PH but the real issue is the CO2 in the closed building. Using Kalkwasser is your best bet to raise the PH. What salt are you using?

 

[Dave Cureton]

Does your 2 part incorporate sodium bicarbonate (baking soda) or carbonate (soda ash)? My experience has been that soda ash will increase PH over baking soda.

 

[Ann Enomy]

I might start with stopping the carbon dosing. Vinegar does impact or lower PH but the real issue is the CO2 in the closed building. Using Kalkwasser is your best bet to raise the PH. What salt are you using?

I am using tropic marin pro reef. Problem I had with kalk was although PH was 8.2 and dKH was still in acceptable range the Calcium got above 600 and the precipitate on all the equipment was crazy. If adjusted dose down to Ca hovering at 500 PH was below 8 again.

 

[Ann Enomy]

Does your 2 part incorporate sodium bicarbonate (baking soda) or carbonate (soda ash)? My experience has been that soda ash will increase PH over baking soda.

Soda carbonate.

 

[Ann Enomy]

I may be wrong but I believe that the highest concentrations of CO2 come from closest to the floor can you extend the air intake for your skimmer to see if that helps

I was under the impression that although CO2 was heavier than O2 that there is no stratification of gasses due to the millions of collisions with all the other gasses every second.

 

[vetteguy53081]

We have about the same ph level. Stable is more important than intended number.
Carbonate is very effective BUT do it in small increments- NOT dump method

 

[Roy Arena]

Okay TMCP is a good salt. If your Alk consumption isn't too much then start dosing Kalk at a half tsp per gallon and increase from there. That way you can maintain your Alk and Can levels and boost the PH. I hope that is of some help.

 

[Ann Enomy]

Are all kalk’s created equal? I’ve only used BRS

 

[Roy Arena]

Yes Calcium hydroxide is pretty much the same. Fully saturated Kalk is two tsp per gallon. You don't need that much typically. If you mix it at that level you can dose less per day. You're only trying to maintain your Alk level not increase it with Calcium hydroxide.