Alk instability

[pjb9166]

We (my son and I) are having a stability issue. For some reason our Alk keeps dropping a whole dkH in a 24 hour period. Nothing but live rock and three frags in the tank for about a month and a half. A torch, frog spawn and a green slimer. The rock has some coralline but not totally covered. We decided to try Kalkwasser. The low Alk and pH wouldn't budge but the Ca sky rocketed to around 500. We did a 100% water change over three days. Wound up having the same instability. So I made a solution of sodium carbonate that should raise the dKH .1 per ml in 25 gal. That is the equivalent to a saturation of 3.34 grams of dry Sodium Carbonate per ml. Our system is 50 gal total. Our doser is accurate and calibrated and we are dosing 30 ml per day. Alk is being measured with a Hanna checker. I'm going to test tomorrow to see if the Alk has held or dropped again. I did notice that the pH was a bit higher today. Having our French doors in the living room and every window in the condo open could definitely helped with that though. The Ca was at 450 two days ago. I'm hoping it drops. I'd like it between 425-430 with Alk at 10-11.1. Absolutely makes no sense why we are burning through so much Alk. We did pick-up 8 more Acro's over this past weekend. So I would expect some Alk to be used but not 30 ml. We are using Red Sea Coral Pro salt and the batches of new mixed water does test out to what the bucket claims. Never had this issue before using Reef Crystals. My trusted brand for over 25 years. One other thing Mag also measures out what Red Sea claims. So that's not low. Any help understanding this would be greatly appreciated. Thank you.

 

[GillMeister]

Do you have a second method to verify the results from your Hanna tester? I made the mistake of trusting one test kit and reacted by raising my alk to 14 without realizing it.

 

[arking_mark]

We (my son and I) are having a stability issue. For some reason our Alk keeps dropping a whole dkH in a 24 hour period. Nothing but live rock and three frags in the tank for about a month and a half. A torch, frog spawn and a green slimer. The rock has some coralline but not totally covered. We decided to try Kalkwasser. The low Alk and pH wouldn't budge but the Ca sky rocketed to around 500. We did a 100% water change over three days. Wound up having the same instability. So I made a solution of sodium carbonate that should raise the dKH .1 per ml in 25 gal. That is the equivalent to a saturation of 3.34 grams of dry Sodium Carbonate per ml. Our system is 50 gal total. Our doser is accurate and calibrated and we are dosing 30 ml per day. Alk is being measured with a Hanna checker. I'm going to test tomorrow to see if the Alk has held or dropped again. I did notice that the pH was a bit higher today. Having our French doors in the living room and every window in the condo open could definitely helped with that though. The Ca was at 450 two days ago. I'm hoping it drops. I'd like it between 425-430 with Alk at 10-11.1. Absolutely makes no sense why we are burning through so much Alk. We did pick-up 8 more Acro's over this past weekend. So I would expect some Alk to be used but not 30 ml. We are using Red Sea Coral Pro salt and the batches of new mixed water does test out to what the bucket claims. Never had this issue before using Reef Crystals. My trusted brand for over 25 years. One other thing Mag also measures out what Red Sea claims. So that's not low. Any help understanding this would be greatly appreciated. Thank you.

When I was automating my Alk/Ca dosing, I came across some numbers that suggested that depending on your inhabitants you will see a daily .5dkh to 4dKH demand.

So 1dKH consumption may be reasonable.

 

[Randy Holmes-Farley]

I agree that 1 dKH is not especially unusual. A soft coral tank can use 2 dKH per day if there is growing coralline.

 

[pjb9166]

Which unit are you trying to calibrate RKE, RKL or Archon? I usually leave it around 20min and don't pay any attention other than making sure in is near what is normal for the module I am using usually keep track of the raw data when I am calibrating so I have an idea what it was before. I have the Archon. It has been quite awhile since I went through a calibration on one of the others.

When I was automating my Alk/Ca dosing, I came across some numbers that suggested that depending on your inhabitants you will see a daily .5dkh to 4dKH demand.

So 1dKH consumption may be reasonable.

I agree that 1 dKH is not especially unusual. A soft coral tank can use 2 dKH per day if there is growing coralline.

Thanks guys. There's nothing in our tank that is quite that demanding. To young of a tank. I could see 1 dkH. But as I pointed out. I'm dosing enough to support 3 (30ml) dKh a day. I'm dropping from 11.1 down to 7.9 in two days. Something is wrong.

 

[Randy Holmes-Farley]

It's always important to tell us up front how many dKH per day you are dosing. If it really is 3 dKH per day and you are losing 1 dKH per day, then yes, that is quite significant.

But I don't see that much being dosed.

This sentence cannot be correct, it is way above saturation.

"That is the equivalent to a saturation of 3.34 grams of dry Sodium Carbonate per ml."

Can you describe exactly what solution you are dosing? Is it just my DIY (BRS recipe, for example)?

I would not try to dose saturated solutions anyway.

30 mL of my DIY #1 (BRS recipe) in 50 gallons is 0.84 dKH per day.

 

[arking_mark]

Thanks guys. There's nothing in our tank that is quite that demanding. To young of a tank. I could see 1 dkH. But as I pointed out. I'm dosing enough to support 3 (30ml) dKh a day. I'm dropping from 11.1 down to 7.9 in two days. Something is wrong.

As @Randy Holmes-Farley suggested if you have a growing population of coralline algae, that could account for the 1dKH daily consumption.

[Please ignore, I misread the 3dKH dosing]

 

[pjb9166]

Thank you for responding. Now you see why I'm concerned. I know I'm running a salt modified out of the bucket to run the trinity at higher levels.

Yes the solution is DIY. The saturation is extremely high. Believe me it took the water being HOT!. I should have know better. I've always used ESV two part and thought I'd try DIYing the Alk portion. Easy enough right.
On further examination today. I noticed my dosing line was a complete crystal and there was fall out in the dosing container. When the saturation cooled the sodium carbonate started to crystallize. So I diluted my solution by half. So instead of 10ml to raise the dkh by 1. I'll be dosing 20ml. I actually followed the mixing rate of Red Sea Foundation A+ powder to Supposedly be the equivalent to the liquid foundation A pre mix, 1ml to 25 gal = .38 or .39 (can't remember off the fly) meg\l or .1dkh. You get the idea. Anyways I cleaned the lines out and the dosing head with citric acid. Recalibrated the doser and for now things seem fine. We'll see over the next 24-48 hours. Thank you again for taking the time to respond to my question. Any other thoughts or suggestions are warmly welcomed.