Sulfur denitrator is lowering tank pH. How to raise pH without raising alkalinity?

[AcroporAddict]

Guys,
I have a sulfur denitrator (H&S 150) that I have been ramping up.

My tank pH has slowly decreased from daylight 8.2 to 7.9 as I increase the drop/sec rate of the denitrator. I use a Nilsen stirrer with my Tunze Osmolator to dose Kalk as well. And I have a calcium reactor. Net volume of system is about 300 gallons.

I checked pH of the tank via a chemical test and it lines up with the tank pH monitor, so I don't think the monitor needs calibration.

KH is good at 9, so I am not having Alk issues, but I don't like the pH where it is. I have the effluent lines from the denitrator and the Ca reactor going into the feed pump for my protein skimmer.

I would like to run the denitrator as high as possible until the nitrate levels are undetectable, then throttle down to a mintenance drip rate, in the meantime keeping pH at decent levels (maybe 8.1-8.2 if possible).

My questions are:

1. What type supplement can I add that will raise pH but not build KH, as my level is good?

2. Do I even NEED to worry about the pH as long as the KH , Ca+, and Mag levels are good?

Thanks.
Dave

So I guess my questions are:

[bertoni]

There's no supplement to raise pH that won't add alkalinity. More aeration might help, although pH at 7.9 isn't that bad, and I wouldn't worry that much. I'd check the pH in the morning, though.

[markm3@link.net]

i was having the same problem and i tryed the algee scrubber lattley which it gives me great results for filteration and my ph always drop to 7.9 after one week trying the scrubber my ph never go less than 8.1 untill lights come back in morning .

[natereinhold1]

I've been running the denitrator that I built for about a year and a half. My ph is stable at 8.2-8.25. If the flow through the denitraor is too slow(drip-rate) it will tend to lower the ph, but is quicker at removing nitrates. I ran mine slow for about 2 weeks and it removed about 20ppm nitrate to 0ppm, but lowered my ph. After the initial removal of nitrates you can significantly speed up the flow through it(steady stream), which in turn doesn't give it enough time to start to lower the ph significantly, and unless you have a really loaded up system, it should still be just fine at maintaining 0ppm. You only really need the slower rate to remove a build up of nitrates, but to maintain it needs a lot less dwell time in the reactor. Also if the flow rate is too slow you can get a build up of sulfates(nasty black crude) in the chamber or rest of system due to too anerobic conditions, and that isn't good. Also, I run my effluent through a 2nd chamber with about 15lbs aragonite to help buffer the ph of the water coming out of the denitrator. Hope this helped some.

[Randy Holmes-Farley]

Once you have depleted most of the standing nitrate, the ongoing depletion of the alkalinity and pH by the reactor will decline a bit. So you might just wait and see what happens with the pH.

Overall, if you are dosing saturated limewater for all evaporated water (and you may not be as reactors often are not effective in saturating limewater), then causing more evaporation or bringing in more fresh air for aeration are the best bets:

Low pH: Causes and Cures
http://reefkeeping.com/issues/2004-09/rhf/index.htm

[Aquarist007]

You might want to setup a refugium with macro algae. This will help boost up your pH and if you run the lights on the refugium opposite to those on the display tank it could stop the nocturnal drop in pH which I believe is related to Bertoni's post in asking you to check the pH in the morning.

[AcroporAddict]

There is a product in the Seachem Aqua Vitro line called Balance that claims to reset the carbonate/bicarbonate ratio, raising pH without affecting calcium levels. It is a 27:1 blend of sodium hydroxide and potasssium hydroxide (both are lye).

Supposed to address the situation of normal calcium and alkalinity levels, but a low tank pH.

Here is a link to product info:http://www.aquavitro.com/Products/balance.html

Think this would work?
Dave

[Randy Holmes-Farley]

It boosts alkalinity and pH exactly the same as limewater does, but doesn't add any calcium. If you are in need of an occasional pH boost, it is likely a fine way to go, although I prefer limewater. It provides about twice the pH boost per unit of alkalinity as does baked baking soda.

[AcroporAddict]

Thanks for your help Randy. Seems you cold make your own version of balance with a 27:1 ratio of NaOH and KOH in RODI water.
Dave

[Randy Holmes-Farley]

Yep.

You're welcome and happy reefing.

[AcroporAddict]

I've dosed the Aqua Vitro "balance" a couple times, and I dosed my own version made with sodium hydroxide. It brings pH up. Alkalinity is up as well. Reading 11 up from 9 a couple days ago. Think I'll lay off for a while and see what the tank does.
Dave