Chronic low PH and inconsistent ALK

[waynemah]

I’ve always had a PH *issue* with my tank. I realize that this is one of those parameters that might be a “new tank” thing, or it might just be the PH it wants to be at, but there are some other un-answered problems that could be related.

It’s twice now with two different salts that I’ve had my ALK drop out, once with Reef Crystals and once with Reef Salts. I don’t believe it’s the salt itself, but my tank seems to consume or precipitate alkalinity. Hopefully, someone can help me piece this together to find the cause.

Water parameters:
Salinity: 1.026 on NSW calibrated refract, 53mS on profilux.
Calcium: 410
ALK: 7.5
MG: 1490
PH: 7.85 - 7.95
Temp: 26C

Other parameters:
Tank up for over 6 months.
Sump Light on reverse cycle.
Effluent from the calcium reactor, this reads 450 CA and 8.4DKH (does this sound about right?)
Was using Reef Salt, 420CA, 7.2DKH, 1280MG and 8.4PH.
Now about to switch to Reef Crystals, 410CA, 11DKH, 1300MG and 7.9 PH.
PH does NOT raise more than .1 when aerated outdoors (although there is a temp change… Likely not a solid test).

Related equipment:
Calcium Reactor with course ARM (high magnesium), 6.8PH.
BRS Magnesium Doser (currently off to bring the number down to lower 1400's)
RO/DI with Tunze ATO.

Recent Events:
Changed to Reef Salt for higher PH with RO/DI to try and resolve PH, ultimately lowered my DKH and seemed to lower PH overall.
Alkalinity drops faster than Calcium, PH also drops when this happens. No clams in the tank.
Tank has some diatoms on the sandbed with a hint of cyano (might be unrelated, not sure).
Changed all RO/DI about a week ago. No change since.

Suggestions on the table (from other people):
Magnesium is too high, taking up “dilution space” causing the alk to precipitate. – Not sure if this is possible???
Add a Kalkwasser solution to a reactor to raise the PH and ALK, have it tied into the ATO. – I’m somewhat afraid of this and it adds a level of complexity. What is the best way to do this?
Change salts to a higher level of ALK and PH (H20cean?) – I’m ok with this… What do you think?

[Proteus]

Your ph is acceptable for the most part. But most Probable is co2 saturation. Your water may be turbulent but still might not be airated to pass that gas on.

Read this
http://reefkeeping.com/issues/2004-09/rhf/index.php

[BlueTang<3]

Are you running the outlet from the ca reactor straight into the tank or through a effluent chamber? I had to get that big tube at the back of the tank to put more media to use up left over co2 as i was having ph issues also. I also run a hose outside for the skimmer intake and bring in fresh air seemed to help out lots.

[Proteus]

May help putting a couple 12 v fans in your cabinet for air
Movement also

[Reef Supplies]

That reading is more than fine, If you try to mess with it you will probably end up doing more harm than good. One of the most important "things" in reef keeping is stability...keeping things as constant as possible.

[Aquattro]

That reading is more than fine, If you try to mess with it you will probably end up doing more harm than good. One of the most important "things" in reef keeping is stability...keeping things as constant as possible.

That reading is also typical when using a Ca reactor, and not something to spend time thinking about. From experience, you will drive yourself nuts worrying about it, and probably not change it anyway. Toss the pH probe, you'll be a happier reefer :)

[subman]

I agree the readings are ok. I've seen the coral growth from pics and it seems everything is quite happy. Just sit back and enjoy.

[reefwars]

That reading is also typical when using a Ca reactor, and not something to spend time thinking about. From experience, you will drive yourself nuts worrying about it, and probably not change it anyway. Toss the pH probe, you'll be a happier reefer :)




+1 on reactor and ph:)

[Myka]

You've been given lots of great advice. If you don't run through an effluent chamber it is not likely that you will be able to raise the pH. Fresh air might help a bit, but probably not much according to your outdoor testing. I also agree though that pH 7.9 isn't a big deal. I don't think your salt has anything to do with it either. Try an effluent chamber. :)

Could you expand on "my ALK drops out"? What number does it go from and to? How long does it take to change?

[PFoster]

I think he just means that his alk readings are the ones that suddenly decrease.

What type of CARX are you using?
A single stage or dual stage?



You can also add media to the second stage of your reactor to moost your mag output.


I dont think it has anything to do with your salt either.

[waynemah]

Could you expand on "my ALK drops out"? What number does it go from and to? How long does it take to change?

The first time around it dropped from 11 - 6.5 within a few days. Initially I thought this was from a phosphate remover, but more likely from the tanks cycle?

The 2nd time was this past week, I've had my ALK drop from 10 - 5 within a month. This drop was more gradual at the beginning (10 - 9 - 7 then 5). I was hoping it would just balance out at 7, but it dropped below.


This is all VERY good advice (Thanks!!! :mrgreen:), I just want to understand it a little better. As I read, PH is critical to the growth of corals and I want to get the best results possible. I believe my aeration tests were poor due to the change in temperature and likely my issue is an excess of C02.

I'm running the Reef Octopus reactor, it has a single chamber. Anyone know of a good *mod* to add another chamber? Could I use a TLF reactor or something?

Wes, when you ran your line outside of the house how does this work in the winter? Does your skimmer freeze up or anything? I'm 100% ok trying this, what size of tube did you use?

Has anyone tried to resolve a similar issue with an HRV / ERV? What is the added cost per month for one of these units? If I have a C02 issue in my house, spending a little money to improve the health of everything living in it is worth the investment.

Thanks for your help everyone!

[waynemah]

May help putting a couple 12 v fans in your cabinet for air
Movement also

I run a dehumidifier most of the time with the sump doors open. This seems to have no effect on the PH. Unfortunately, I believe my house might be too air tight (previous owner went crazy with heat/cooling efficiency upgrades).

This might be a good idea anyways, it does get somewhat stale in there.