Very low pH and Alk

[Rick's Reefing Adventures]

Hello!

I just did a water change and tested my water afterward, but to my surprise, my pH dropped from 8.4 to 7, and my alkalinity fell from 7.7 to 5.8. I recently upgraded tanks and had to remove my skimmer since it no longer fit. Technically, the skimmer itself fits, but the collection cup doesn’t.

For now, I’ve reinstalled the skimmer, but I’m running it without the cup. Is it okay to run it this way temporarily? Also does anyone know a good but slim skimmer? Otherwise I’m going to have to alter the cup…

Regarding the alkalinity, I’ve never seen it drop this low before. My salt mix usually measures around 8 dKH. Could raising the pH help stabilize or increase my alkalinity, or should I start dosing?

On a positive note, all my corals are still open and looking fine so far.

 

[Randy Holmes-Farley]

I don't think the pH is really 7.

Do you have any of that new salt water remaining? If the alk measurement is correct, something was terribly wrong with it. Try measuring the alk in it.

I'd focus on alk for now, and let pH do what it will. pH is much harder to actively control than alk.

 

[Rick's Reefing Adventures]

I don't think the pH is really 7.

Do you have any of that new salt water remaining? If the alk measurement is correct, something was terribly wrong with it. Try measuring the alk in it.

I'd focus on alk for now, and let pH do what it will. pH is much harder to actively control than alk.

Just for now I put in a cup-less skimmer and added a longer tubing through the window. Let’s see if that helps.

This isn’t a new batch of salt so I’m super confused. I’m going to mix 1 gal of salt water to check those parameters. I will let you know.

 

[Miami Reef]

For now, I’ve reinstalled the skimmer, but I’m running it without the cup. Is it okay to run it this way temporarily?

Sure. It won’t hurt anything, and it will help with aeration.

What alkalinity and pH test do you use? I agree that testing the new salt is wise.

 

[Rick's Reefing Adventures]

Sure. It won’t hurt anything, and it will help with aeration.

What alkalinity and pH test do you use? I agree that testing the new salt is wise.

I use Hanna for alk. Salifert for pH and alk when my Hanna gives a weird reading. I test all params weekly and everything was normal. Also not a new batch of sand. I’m halfway through a 22KG bucket.

 

[Miami Reef]

Both Salifert and Hanna measured the same alkalinity drop after the water change?

You can toss out that Salifert pH kit. Kits are highly inaccurate for measuring pH. We use probe style tests for seawater tanks.

It’s extremely difficult for pH to drop below 7.8 in reef tanks with normal alkalinity.

 

[Rick's Reefing Adventures]

Both Salifert and Hanna measured the same alkalinity drop after the water change?

You can toss out that Salifert pH kit. Kits are highly inaccurate for measuring pH. We use probe style tests for seawater tanks.

It’s extremely difficult for pH to drop below 7.8 in reef tanks with normal alkalinity.

Yes both showed the same drop. My only guess is that I might have made a mistake somewhere with the waterchanges, but all other parameters are fine. I also got a pH probe but I need to recalibrate it. The salifert test might be inaccurate, but it’s been giving 8,4 readings for 1.5 years, so if it now reads way lower, I think I can assume it is actually lower. My new batch of water is almost done so I can test the parameters.

 

[14 foot reef]

Take @Randy Holmes-Farley 's advise, stop worrying about pH concentrate on alk.

Do you have any of the new water change water left over ? If so test it, if not. Assume the problem is there, and mix up a new small 5 gallon batch and test it for possible salt issue, if it test ok within the expected perimeters, then you know it was a mixing error.
The Skimmer also should be no concern right now, concentrate on the alk.

 

[Rick's Reefing Adventures]

I don't think the pH is really 7.

Do you have any of that new salt water remaining? If the alk measurement is correct, something was terribly wrong with it. Try measuring the alk in it.

I'd focus on alk for now, and let pH do what it will. pH is much harder to actively control than alk.

Take @Randy Holmes-Farley 's advise, stop worrying about pH concentrate on alk.

Do you have any of the new water change water left over ? If so test it, if not. Assume the problem is there, and mix up a new small 5 gallon batch and test it for possible salt issue, if it test ok within the expected perimeters, then you know it was a mixing error.
The Skimmer also should be no concern right now, concentrate on the alk.

I just tested my new mix of water, and the Hanna reads it at 7.4. Tank water at 5.8. Not sure what happened, but the salt seems fine? What would be the best way to raise it back up? Daily 10% water changes?

 

[Randy Holmes-Farley]

I just tested my new mix of water, and the Hanna reads it at 7.4. Tank water at 5.8. Not sure what happened, but the salt seems fine? What would be the best way to raise it back up? Daily 10% water changes?

Retest the tank. Now way can a water change with water at 7 dKH and tank at 7.7 dKH end up below 6 dKH in the tank.

That said, normal alk consumption a tank independent of water changes will deplete alkalinity and it needs to be added back.

 

[14 foot reef]

What is your total volume size of reef & sump ?

Any Chance there was some muriatic acid in the water change bucket from tank pump maintenance ?

 

[Rick's Reefing Adventures]

Retest the tank. Now way can a water change with water at 7 dKH and tank at 7.7 dKH end up below 6 dKH in the tank.

That said, normal alk consumption a tank independent of water changes will deplete alkalinity and it needs to be added back.

I just retested my tank and it’s still at 5.8… but the freshly mixed water reads at 7.4 while the box says it should be 8.

What is your total volume size of reef & sump ?

Any Chance there was some muriatic acid in the water change bucket from tank pump maintenance ?

It’s a 25G AIO. I did clean my pumps 2 weeks ago with citric acid.

 

[14 foot reef]

What all animals, coral, fish, and inverts do you have in it?

When starting post like this, all of this info should have been in the very first posting just for future help.
Let us know the livestock, and then we will advise.

 

[Rick's Reefing Adventures]

What all animals, coral, fish, and inverts do you have in it?

When starting post like this, all of this info should have been in the very first posting just for future help.
Let us know the livestock, and then we will advise.

Alright never had an Alk problem before so I didn’t know.

2 Clowns
1 Blood shrimp

Caulastrea
Zoa garden
10 Euphyllia

 

[14 foot reef]

If you are certain the Alk is that low, I would assume the citric acid might have been left in the bucket. That is a guess only.

If it were me, and I had a way to do a near 100% water change, that is what I would do. You have a huge investment there in corals, so this is your personal choice, I'm not saying you have to do it, I'm saying I would.

Also how old is this system, it looks very very new.

 

[Ben's Pico Reefing]

What is the salinity in the tank?

 

[Rick's Reefing Adventures]

If you are certain the Alk is that low, I would assume the citric acid might have been left in the bucket. That is a guess only.

If it were me, and I had a way to do a near 100% water change, that is what I would do. You have a huge investment there in corals, so this is your personal choice, I'm not saying you have to do it, I'm saying I would.

Also how old is this system, it looks very very new.

I can do a 90-100% waterchange!

This system in particulair is a month old. I used to have a 15G that I upgraded a few weeks ago. Corals have been in the tank for roughly a week now. Biomedia, a few rocks and all livestock were transfered.

What is the salinity in the tank?

35ppt

 

[14 foot reef]

^^^^^ What Ben Said, whats the chances you forgot Salt ? its happened before to others.

 

[14 foot reef]

If the System is that new, I wouldn't be afraid of the 90-100% water change as its not that stable right now anyway.

Again, what I would do, this is ultimately up to you.

 

[Rick's Reefing Adventures]

If the System is that new, I wouldn't be afraid of the 90-100% water change as its not that stable right now anyway.

Again, what I would do, this is ultimately up to you.

Well I’ve only been in this hobby for 1,5 years, and as this was my first time moving tanks, I’m just going to listen to you and do a 90% waterchange.