High pH question

[USMA36]

Last week I switched from dosing 5000ml of lime water and .6 dkh worth of carbocalcium to Randy’s high ph 2/3 part. The elevated pH is outstanding. Maybe a little to good. I’m averaging lows of 8.2 to highs of 8.5 unless a little less if the whole family is home. I’m also running a jumbo brs co2 scrubber. Since I switched over I can’t pump enough alk in to get my dkh to 8.5. I am running a trident and just tried to have it manage the dosing after 1 week of watching but I’m up to 287 ml of alk and only 158 of calcium. My calcium level is 460 alk 7.99 and mag is 1300. Is something wrong? Could it be precipitating out? Both calcium and alk are being dosed into high flow areas. The alk drops directly over the intake of my return pump.

 

[Cory]

Yes it could be precipitated out. But when was you ph probe last calibrated? I was running the same ph levels and hadn't calibrated my ph probe for a year. After calibration ph is 8 to 8.16 daily. Verfied with a saliftert ph test too.

 

[ReefHunter006]

I run my PH much higher using kalk and 2-part. Probe is calibrated quarterly and replaced annually.

I am not recommending anyone run it that high, but it’s not as cut and dry as people make it sound. 8.5 is more than acceptable.

I think you are seeing an increase of demand and precipitation. Percipitation is always happening to a small degree, higher ph will increase it. I dose between 3.7-4.5 dkh a day of additive between the two. At a lower ph of 8.1-8.3 I would dose nearly half that amount of about 2dkh-2.5dkh.

I recognize there are situations where you might dose more of one 2 part than the other but I don’t believe with the information present that your in that camp. I would match your cal dosing to be the same as your alk as you change it.

for instance last week, my alk portion of the 2 part went from 175 to 145 in 24 hours. Cal was changed to match immediately.

 

[Randy Holmes-Farley]

Yes, demand for alk and calcium rises as pH rises. The demand comes both from biological and abiotic formation of calcium carbonate.

I don’t think pH 8.5 is too high (mine peaked higher), but reducing the efforts to boost pH is a fine idea.

 

[USMA36]

Yes it could be precipitated out. But when was you ph probe last calibrated? I was running the same ph levels and hadn't calibrated my ph probe for a year. After calibration ph is 8 to 8.16 daily. Verfied with a saliftert ph test too.

Probe was recently calibrated.

 

[USMA36]

Yes, demand for alk and calcium rises as pH rises. The demand comes both from biological and abiotic formation of calcium carbonate.

I don’t think pH 8.5 is too high (mine peaked higher), but reducing the efforts to boost pH is a fine idea.

Yes, demand for alk and calcium rises as pH rises. The demand comes both from biological and abiotic formation of calcium carbonate.

I don’t think pH 8.5 is too high (mine peaked higher), but reducing the efforts to boost pH is a fine idea.

First and foremost thank you for all your help lately. I apologize for hammering you with questions. I’m worried about my dosing. I started out about a week ago dosing 200ml of your sodium hydroxide solution a day to maintain 8dkh My alk has steadily been falling now sitting between 6.5 and 7. I’m up to 350ml a day now but I can’t get my dkh to raise and my pH is steadily rising (topped out at 8.75 yesterday and only dropped to 8.58 overnight) can my alk consumption have gone from a steady 1.5 dkh to 2.5dkh plus a day? I’m worried that if I continue to raise the dose that I’m going to cause a big alk spike. I use a trident to measure but I double check dkh using a Hannah checker and it’s always within .4 dkh of the trident. I don’t see precip building up or milky water I have the alk dosing directly above the intake of my return pump. I will try moving to a more turbulent area perhaps skimmer outflow. Will raising magnesium to 1350 and or lowering calcium to 415 help if it is precipitation? Tank is 200 gallons total volume SPS dominant with a about 10 larger SPS and lps colonies as well as 15 to 20 frags. I discontinued using my co2 scrubber and sealed up my house to help lower the ph. Usually when I do that my ph plummets to 7.6 at night but no effect. Prior to switching to sodium hydroxide I was dosing 1dkh of kalk and .5 of calcium formate my ph was 7.8 to 8.0 while running a large co2 scrubber. I am also starting to doubt my pH probe. I ordered a new probe but it won’t arrive until Thursday. I tried to recalibrate it yesterday and it failed. It did read correctly in the calibration solutions so maybe it’s not too far off.

 

[USMA36]

Bump

 

[Randy Holmes-Farley]

I'd recommend using a sodium carbonate buffer instead of sodium hydroxide since the pH is getting quite high (assuming it is accurate).

 

[USMA36]

Thanks. If the ph starts dropping will the alk spike? Can a mix of the two be used to get a smaller ph bump?

 

[Randy Holmes-Farley]

Thanks. If the ph starts dropping will the alk spike? Can a mix of the two be used to get a smaller ph bump?

Yes, you can mix them. I’d reduce the alk dosed as you reduce the pH

 

[Cassklar]

Hello I was looking at this thread what would be the mixture to lower ph a little? sodium hydroxide and sodium carbonate what would the ratio be I was having the same issue the hydroxide was raising the ph but my alk could not keep up

 

[Cassklar]

What is sodium bicarbonate and where can I purchase that

 

[USMA36]

Hello I was looking at this thread what would be the mixture to lower ph a little? sodium hydroxide and sodium carbonate what would the ratio be I was having the same issue the hydroxide was raising the ph but my alk could not keep up

I started at 50/50 2 gallons of each. That dropped my ph to 8.1 max. I’m going to switch to 3 gallons sodium hydroxide to 1 gallon of calcium carbonate. That will hopefully get me in the 8.3 ballpark. droppong my ph from 8.7 to 8.1 reduced my alk usage greatly. I went from 350ml to 170ml a day, I was def losing a lot to precipitation, so keep an eye out for that drop in uptake or you’ll spike your alk levels. Sodium bicarbonate is baking soda. Sodium carbonate is soda ash. You can make sodium carbonate from baking soda by baking it in an oven at 300 for 1 hour.

 

[Cassklar]

Thank you can we buy sodium bicarbonate from somewhere instead of Baking baking soda thanks

 

[Randy Holmes-Farley]

Thank you can we buy sodium bicarbonate from somewhere instead of Baking baking soda thanks

I think you need to step back and read more about dosing before jumping in.

What is your pH and alkalinity at the moment?

Sodium Bicarbonate is just baking soda from the grocery store.