Difficulty keeping Alkalinity stable!

Greenstarfish03 · Sep 16, 2020

I have been using the 2 part formula from reef alkammy by Randy for many years w/o issue. I have had my current tank running for maybe 4 years. 100g with about 50g in the sump. I use a Apex and 2 BRS dosing pumps to dose both calcium and alk. Mixed reef mostly softies and lps and some sp's. I havent changed anything recently and only tweaked the dosing times here and there over the years. About 2 weeks ago I noticed my spa's were not doing well so I checked my alk and it was low 7 dkh. It stays pretty stable between 9 or a shade lower and 10. I manually dosed 40ml of alk over about an hour in addition to my regular dosing. I checked my program and thr dosing pump it seems to be working fine. When I manualy dose it goes up a little but it will not stay up if I don't manualy dose it keep dropping. I have been manually dosing between 40 and 80ml of 2 part alk solution in addition to my normal schedule for 8 days and the same thing back down to 7 if I don't manually dose. MG is 1380, CA was 525 today and has been between 500 and 525 the last 8 days. PH has been ranging a little high lately. According to my probe at the end of August it had been staying between 8.2 and 8.3 and now its been ranging between 8.5 and 8.6 for reason. I double checked the ph with a test kit and the best I can tell its about 8.6. Its hard to distinguish the colors in that area on my red sea kit. My oral consumption shouldn't be much other then normal. Any thoughts on why I'm having problems keeping my alk stable all of a sudden?

Thanks

Crustaceon · Sep 16, 2020

If you’re dosing the “baked baking soda” (sodium carbonate) recipe, your rapid loss of alk could be due to precipitation. That spike in ph points to that being the issue and is something that plagues reefers who use kalkwasser. Sodium carbonated needs to be added very slowly to a high flow area of a tank, such as directly into a power head. This will reduce the ph impact and should reduce the chance the precipitation. Shoot for a 1-2 ml per minute addition rate. Don’t just dump it all in.

Greenstarfish03 · Sep 16, 2020

Crustaceon said:
If you’re dosing the “baked baking soda” (sodium carbonate) recipe, your rapid loss of alk could be due to precipitation. That spike in ph points to that being the issue and is something that plagues reefers who use kalkwasser. Sodium carbonated needs to be added very slowly to a high flow area of a tank, such as directly into a power head. This will reduce the ph impact and should reduce the chance the precipitation. Shoot for a 1-2 ml per minute addition rate. Don’t just dump it all in.

I dont bake the baking soda so Im using bicarbonate already I should have mentioned that earlier. My dosing pump runs for 5 mins and 55 seconds per hour on the hour 24/7 and im pretty sure it is between 1-2 ml per minute. I think I dose slowly. I have been using this same method for many years without this issue. The only time I dump any in is in the last 8 days when the level keeps dropping using my normal method. Im leary to make major changes to my dosing time since this has been working fine for years.

Randy Holmes-Farley · Sep 17, 2020

The high pH will drive precipitation, and if it is accurate, more aeration will bring the pH down. Do you have a skimmer? Its not apparent why the pH would rise, however, and it may be inaccurate.

I'd also double check the alk measurements as very high alk will itself lead to high pH, and would explain why more dosing was needed.

Greenstarfish03 · Sep 17, 2020

Randy Holmes-Farley said:
The high pH will drive precipitation, and if it is accurate, more aeration will bring the pH down. Do you have a skimmer? Its not apparent why the pH would rise, however, and it may be inaccurate.

I'd also double check the alk measurements as very high alk will itself lead to high pH, and would explain why more dosing was needed.

Thanks Randy. I do have a skimmer. I ordered a new reagent for my Hannah alk tester and the new reagent was different. I used the old reagent (not expired) and got 7.25 and then with the new reagent 8.4 dkh. So that is odd for sure. I recalibrated my ph probe and it was still at 8.53 right after I calibrated it. My alk dosing is supposed to run at the top of the hour and calcium at the bottom but when I was just downstairs I noticed they were both running at the top of the hour so I need to see what is going on with my apex. I will look into that more tonight and post back. Would I just run a air stone or something in my sump to add more co2?

ReefHomieJon · Sep 17, 2020

525 cal? A little high too no?

Greenstarfish03 · Sep 17, 2020

ReefHomieJon said:
525 cal? A little high too no?

Definitely higher then I would like it to be.

ReefHomieJon · Sep 17, 2020

How did it elevate so much?

Greenstarfish03 · Sep 18, 2020

ReefHomieJon said:
How did it elevate so much?

Good question that I hadn't thought to much about. I went back through my logs and it looks like it was in the 300's in December and it was 400's in January then shortly after it went about 500 and it has stayed between 500 and 525 since. I looked back through my notes at that time and it looks like my alk pump broke in December so I was manualy dosing for a week or so.while I waited for the part. Probably more importantly I changed my ca dosing program to dose opposite my alk schedule so at the bottom of the hour. I dont have notes on when I fixed it but it was a while later but I messed up the program in my apex and it was dosing ca too often which I assume raised the ca level and I've never taken any action to.reduce it other then I fixed my ca dosing program. I guess I will reduce my dosing time for ca slowly and let it come down some. Does the CA tie into the issue with the alk some how?