Another dosing help thread..

[vandy]

Hey all! I'm looking for a little critiquing of my dosing regime. The goal of this thread is to eventually "chase" ph to the 8.1-8.3 range. Setting the stage: my tank is a 100gal IM 100INT, roughly 9 months old, and heavily leaning towards an SPS tank with 15+ "mini colony" sized pieces (>8"). The tank also has tons of LPS and coralline growing like crazy. All my SPS have been growing great over the last few months, but I think they will really excel under the slightly higher ph.

Current ph range: 7.75-8.0. Some days even lower than 7.75. Assuming ~.5 probe inaccuracy

My current dosing scheme:
Calcium reactor @ 6.5ph being dosed 24/7 by a doser running 120ml/min.
Full saturation kalkwasser dosed via kalk stirrer. 4400ml/day, dosing split into 48 times throughout the day
Sodium Hydroxide - dosing 100ml/day split into two dosing periods: 60ml in the morning (dosed 8am-10:30am), 40ml in the evening (11pm-3am / 10ml/hr). Mixed to the same concentration as the soda ash recipe.

I also have a CO2 detector right next to my tank. I know these might not be the most accurate, but it consistently reads 402-420ppm throughout the day. I keep a window open and pump fresh air towards the tank. Just in case, I also have a CO2 scrubber on my skimmer.

To offset the ph depression from the calcium reactor, I run it through a 2nd chamber, and I also put the output of the dosing line into a cup that has an air bubbler, which overflows into the sump.

Anybody have any other recommendations to raise my PH? I'm open to adjusting any ratio that I am currently using. I would like to try to avoid using an algae reactor, as my nutrients are pretty dialed with my feeding regime.

The sodium hydroxide dosing in the morning before the lights turn on gets me to my max PH faster, but still cant climb over to the 8.1 territory.

Any help would be greatly appreciated!

 

[Randy Holmes-Farley]

More aeration will raise the pH, if it’s accurate.
Try this test:

pH and the Reef Aquarium - REEFEDITION

by Randy Holmes-Farley For many aquarists, pH is not something that they have much experience with aside from their aquarium. For many, pH is almost a black box measurement: something to be considered, but whose physical meaning makes little sense to them. This article will Read more here...

www.reefedition.com

The Aeration Test

Some of the possible causes of low pH listed above require an effort to diagnose. Problems 3 and 4 are quite common, and here is a way to distinguish them. Remove a cup of tank water and measure its pH. Then aerate it for an hour with an airstone using outside air. Its pH should rise if it is unusually low for the measured alkalinity (Figure 2). Then repeat the same experiment on a new cup of water using inside air. If its pH also rises, then the aquarium’s pH will rise simply with more aeration because it is only the aquarium that contains excess carbon dioxide. If the pH does not rise in the cup (or rises very little) when aerating with indoor air, then that air likely contains excess CO2, and more aeration with that same air will not solve the low pH problem (although aeration with fresher air should). Be careful implementing this test if the outside aeration test results in a large temperature change (more than 5°C or 10°F), because such changes alone impact pH measurements.

 

[scotty333]

Oh my , I’m not sure I wanted to see this thread but here it is haha

Ok so ,
I’m somewhat an expert here having tried everything
Can you tell your kh please

 

[vandy]

More aeration will raise the pH, if it’s accurate.
Try this test:

pH and the Reef Aquarium - REEFEDITION

by Randy Holmes-Farley For many aquarists, pH is not something that they have much experience with aside from their aquarium. For many, pH is almost a black box measurement: something to be considered, but whose physical meaning makes little sense to them. This article will Read more here...

www.reefedition.com

The Aeration Test

Some of the possible causes of low pH listed above require an effort to diagnose. Problems 3 and 4 are quite common, and here is a way to distinguish them. Remove a cup of tank water and measure its pH. Then aerate it for an hour with an airstone using outside air. Its pH should rise if it is unusually low for the measured alkalinity (Figure 2). Then repeat the same experiment on a new cup of water using inside air. If its pH also rises, then the aquarium’s pH will rise simply with more aeration because it is only the aquarium that contains excess carbon dioxide. If the pH does not rise in the cup (or rises very little) when aerating with indoor air, then that air likely contains excess CO2, and more aeration with that same air will not solve the low pH problem (although aeration with fresher air should). Be careful implementing this test if the outside aeration test results in a large temperature change (more than 5°C or 10°F), because such changes alone impact pH measurements.

Should have mentioned that in the post. I've done the PH test a month or so ago, and its come within ~.1 of outside air with inside air (tested with a handheld ph probe). This has led me to believe that the co2 detector inside next to the tank isn't too inaccurate.

 

[p1u5h13r4m24]

If it helps I have fresh air supply to my hvac system. Fresh air line to the skimmer. I only dose alk and all for reef. My ph still drops to 7.8 at night and goes to 8.4-8.5 during the day. I’ve calibrated and switch probes and those are accurate. I think it’s tough to not get ph drops at night and idk how people do it.

 

[vandy]

Oh my , I’m not sure I wanted to see this thread but here it is haha

Ok so ,
I’m somewhat an expert here having tried everything
Can you tell your kh please

kh varies from 7.5 to 8 throughout the day

 

[vandy]

If it helps I have fresh air supply to my hvac system. Fresh air line to the skimmer. I only dose alk and all for reef. My ph still drops to 7.8 at night and goes to 8.4-8.5 during the day. I’ve calibrated and switch probes and those are accurate. I think it’s tough to not get ph drops at night and idk how people do it.

I have a window open with a fan blowing towards the tank. i've tried an outside line to the skimmer but found it didn't really make much difference since co2 in the room is similar to outside.

edit: wish I had that range though! i can write off some margin of error with ph due to ph probe inaccuracy but .5 difference is pretty drastic!

 

[rishma]

I have a window open with a fan blowing towards the tank. i've tried an outside line to the skimmer but found it didn't really make much difference since co2 in the room is similar to outside.

edit: wish I had that range though! i can write off some margin of error with ph due to ph probe inaccuracy but .5 difference is pretty drastic!

Try the outdoor aeration test as Randy suggested unless you are measuring CO2 inside the house. The results surprised me.

 

[vandy]

Try the outdoor aeration test as Randy suggested unless you are measuring CO2 inside the house. The results surprised me.

See my comment above

 

[rishma]

See my comment above

I found that with outdoor aeration far exceeding the skimmer intake volume, the results were significant. The outdoor air to the skimmer just wasn’t enough.

 

[vandy]

I found that with outdoor aeration far exceeding the skimmer intake volume, the results were significant. The outdoor air to the skimmer just wasn’t enough.

When you say outdoor aeration what do you mean? I have a window open with fresh air blowing to the tank

 

[scotty333]

If it helps I have fresh air supply to my hvac system. Fresh air line to the skimmer. I only dose alk and all for reef. My ph still drops to 7.8 at night and goes to 8.4-8.5 during the day. I’ve calibrated and switch probes and those are accurate. I think it’s tough to not get ph drops at night and idk how people do it.

There’s no way your lows 7.8 and high 8.5 it’s normally .2 difference

 

[scotty333]

kh varies from 7.5 to 8 throughout the day

There’s your answer then

 

[vandy]

There’s your answer then

Can you expand on what you mean?

 

[rishma]

I found that with outdoor aeration far exceeding the skimmer intake volume, the results were significant. The outdoor air to the skimmer just wasn’t enough.

When you say outdoor aeration what do you mean? I have a window open with fresh air blowing to the tank

A huge air pump to a huge airstone in the overflow or sump.

If the aeration test recommended by Randy shows no significant improvement then I wouldn’t bother.

I see a significant difference with forced aeration vs my windows and doors open with fan circulation .

 

[vandy]

A huge air pump to a huge airstone in the overflow or sump.

If the aeration test recommended by Randy shows no significant improvement then I wouldn’t bother.

I see a significant different with forced aeration vs my windows and doors open with fan circulation .

Interesting. I've seen this used before too but figured between my oversized skimmer and the airstone used to raise the ph of the effluent, I was covered

 

[rishma]

There’s your answer then

Can you expand on what you mean?

Your fully aerated pH will alkalinity 7.5-8 will be 8.25-8.3

 

[rishma]

A huge air pump to a huge airstone in the overflow or sump.

If the aeration test recommended by Randy shows no significant improvement then I wouldn’t bother.

I see a significant different with forced aeration vs my windows and doors open with fan circulation .

Interesting. I've seen this used before too but figured between my oversized skimmer and the airstone used to raise the ph of the effluent, I was covered

After the skimmer attempt, I went through three air pumps, medium, big, the huge.

The skimmer and first air pump didn’t do much.

It took a lot of air.

 

[vandy]

Your fully aerated pH will alkalinity 7.5-8 will be 8.25-8.3

Got it. I'll give more aeration a shot. Where did you come up with the 8.25-8.3 number?

 

[rishma]

Got it. I'll give more aeration a shot. Where did you come up with the 8.25-8.3 number?