pH management in an SPS tank

[Chyendra]

I just got my RKL & pH probe set-up on my 45 gallon mixed reef. I'm working on stabilizing my parameters hoping to improve my SPS color and growth.

After calibrating my pH probe, I discoverd my pH is running between 7.96 -7.99 throughout the day. It dropped last night after I changed my GFO and it got as low as 7.85 early this morning. I know this is really low, so I'm wondering what steps I should start taking to boost & stabilize my pH.

I'm trying to keep my alk at 8 dkh since I'm dosing vodka, and even though I'm dosing BRS recipe 2 (soda ash) for my alk first thing in the morning, my daily dose (10ml) only raises the ph about 0.1.

I'm thinking my tank needs more oxygen, but it's still winter here in wisconsin, so I won't be opening any windows until late april.

I run a fuge with a 24/7 photoperiod.

So now I'm thinking whether or not I should start dosing kalk, and how much. I'm concerned about my ability to keep a stable ph while dosing kalk, and I'm wondering if having a low, stable pH would be better than a high, unstable ph.

Thoughts? suggestions?

 

[twon8]

I top off with kalk and only use two part for occasional suppltementation. IMO a higher ph is beneficial.

 

[SPSEMPIRE]

add the kalk.

a kalk reactor with a mixing pump set on a pH monitor is a great way to control pH. The kalk reactor is my backbone to keeping SPS corals

 

[krazysps]

Agreed kalk is the best way to keep it stable. Works better than a fuge on reverse lighting IMHO.

 

[Chyendra]

Would kalk dosing boost my Alkalinity higher than it should be for someone who is carbon dosing?

 

[StarF]

its pretty normal that the ph raises and falls during the day and night, as long its in within 7.8-8.3 i wouldent do anything special to keep it stable.

if you are getting the ph swings due to other factors like calc reactor or sulfor filter, then a kalkmixer could be a good way to fix it. Also getting the skimmer to take fresh air from outside, via a hoze can raise the ph aswell..

 

[Chyendra]

So you're saying that if my ph is stable between 7.8-7.9 I shouldn't try to mess with it, just let it be?

 

[StarF]

yup, althought its a bit low. As long your corals seem happy, and a growing i wouldent toucn anything.

my ph, starts on 7.89 and ends at 8.06 atm.. its all natrual that the ph rises during the day, and falls in the night.

if you want it to be raised a bit, try making it so, your skimmer takes fresh air from outside. (i had to do that)

 

[SPSEMPIRE]

yup, althought its a bit low. As long your corals seem happy, and a growing i wouldent toucn anything.

my ph, starts on 7.89 and ends at 8.06 atm.. its all natrual that the ph rises during the day, and falls in the night.

if you want it to be raised a bit, try making it so, your skimmer takes fresh air from outside. (i had to do that)

ditto, pH stability is much better than shooting for a number. The problem is that you are going to need to supplement calcium and alk as your corals grow. The supplements usually raise pH.

 

[Chyendra]

Ph was 7.74 this morning... how low is getting too low?

Sorry, I didn't mention that I already dose BRS two-part, and I've been adding my Alk recipe 1 first thing in the morning, which boosts the ph slightly, but not a lot (from 7.74 to 7.8 this morning)

My skimmer doesn't have an air input that I could tube to outside... plus I live in an apartment, so wall drilling is out.

I wouldn't care so much except that my SPS have always been brown and have never colored up, so I've been trying to trouble shoot this (more lighting, stable alk, lowering N & P, stable temp, stable salinity... ect.) so I'm wondering if low ph could be the cause.

 

[dixiedog]

FWIW, a reverse photoperiod for the fuge is said to create more stable pH than the 24/7 photoperiod you're running now.

 

[Chyendra]

FWIW, a reverse photoperiod for the fuge is said to create more stable pH than the 24/7 photoperiod you're running now.

Yeah, I was wondering about that too? I will get another timer and see if switching it to a reverse photoperiod will help.

 

[sirreal63]

Brown sps is a sign of too many nutrients or not enough light, it is not ph related. What are your nitrate and phosphate readings, and what lighting do you have?

 

[Chyendra]

My nitrates have been 0.5 or less for almost 2 months, my phosphates have always been undetectable in my salifert, and I've been running GFO for 3 months (I change it every 3wks)
My alk has been stable between 7.7-8.3 dkh for about a month.
I run a single 250w DE Phoenix 14k MH w/ a 6 hour photoperiod (18" deep tank, 24"x24" footprint)

Believe me, I've been ruleing out the possible problems left and right and now I feel like I'm spliting hairs. My SPS aren't deep brown, more like light tan, but not bleached.

 

[sirreal63]

It may take more time, I usually try and get browned out sps from lfs's and sometimes it takes 6 months or more for them to color up, usually less but there are a few that have been stubborn. I know you are striving for an ULNS with the vodka, but I would bump up the alk a little. Hobby grade test kits are notoriously inaccurate. I have dosed VSV since about 2005, keep my alk around 10 (Salifert) and have never had burned tips. I know some have had that issue with ZEO, but that is a severely ULNS. Give it more time, and I would bump up the alk a bit.

 

[Chyendra]

I've always had better results with a higher alk (in the 10dkh range) in the past, before I was dosing vodka. (By better results, I mean my coraline algea grew faster, and my SPS grew but were brown.)

All that to say, I would LIKE to have a higher alk. I will consider slowly raising it and watching carefully for any burnt tips.

BACK to the ph... is 7.74 dipping too low? It wouldn't that hard to start dosing kalk, either in my top-off water, a dripper, or I could run a doser w/ my RKL and pH monitor. But simpler is better if the results are the same.

 

[wakeboardgeek]

I try to keep my pH between 8.1 (in the morning) and 8.3 (after the lights go out). Occasionally, I'll add some vinegar to drop my pH if it gets too high (I run BB system).

 

[sirreal63]

It is extremely rare for ph to drop dangerously low, long ago I tried chasing ph numbers and my system suffered, at the advice of the owner of my favorite LFS, I stopped trying to make the ph what I wanted and just let it be what it wanted. Within weeks everything started to look better and my sps started to grow. He was right, and my ph stayed in the low to mid 7's and everything was fine. Where we get into problems is trying to reach a ph number that we want, and do things to force it, this causes issues, usually with alk.

7.4 is not too low, and kalk is a wonderful thing, in moderation. Your top off water is an excellent place to use it, provided you don't add too much at once. I prefer an IV hooked up to a gallon jug, but I don't drip kalk very often, my CaRx handles the tanks needs, but when I have it down for cleaning, I do drip kalk. Keep in mind too that your ph probe may not be 100% accurate

I wouldn't worry about the ph, it sounds like you have taken the right steps to getting the chemistry under control, removing the excess nutrients, now comes the hard part...patience.

 

[dzhuo]

7.4 is not too low, and kalk is a wonderful thing, in moderation.

Are you running with 7.4 and not seeing any issues? I haven't heard anyone running pH this low.

My skimmer doesn't have an air input that I could tube to outside... plus I live in an apartment, so wall drilling is out.

Have you consider a CO2 scrubber? Most low pH is caused by excess CO2.

I agree with everyone that as long as your pH stays above 7.8, it's probably nothing to worry about.

 

[SPSEMPIRE]

I would bet that most of the people with a regular pH reading below 7.7 would be running a calcium reactor.