Low Alk? Even with fresh mix

[c0mf0rt]

I'm using Fritz RPM and noticed my alk in my tank was 3 this morning! So I tested a fresh mix I made just a day or two ago and it's reading 4. This same test kit measured it to be correct just a few months ago so I know it's not the kit. How in the world is my Alk so low?

 

[MPCReefer]

What temp is your water when mixing? How fast are you adding the salt when mixing? I found that higher water temp >75 or so and adding salt too fast can somehow precipitate out alkalinity during mixing. Cooler water and slower mixing allowed me to raise alk to 10 with Fritz Red box.

 

[c0mf0rt]

Yeah I'm using the red box. Yep is probably in the 60s, it's fresh out of the well/rodi unit. Maybe I'm mixing it too fast. I add a half a cup at a time and stir.... how quickly do you do it?

 

[c0mf0rt]

....and to anyone who reads this in the future..... There are two answers on the web for raising the alk in the tank. 1 tsp per 10 gal or 1 tbsp per 10 gal. The tsp answer is correct. I didn't find it until later and used tbsp. My alk just went up five points! Crap, hopefully everything doesn't die!

 

[BoxKing]

I use RPM Blue - 5 gl changes at a time. Temp of my water at the time I add salt is sub 70*. I add roughly all my salt to the bucket within a few minutes, by lightly dumping in a little at a time. I use a 450gl/hr pump to mix, which also brings the water temp without a heater to roughly 77* - I mix for 2-3 hrs prior to use. Alk from the bucket is always around 8.5 DKH

Im leaning towards your testing method to be out of whack here... 3 in the tank, 4 from the pre-mix sounds about right, but obviously with values far lower than desirable . Maybe your numbers are really 8 in bucket, 7 from the tank?

 

[c0mf0rt]

Thanks for the feedback. I'm using a Red Sea alk test and it's pretty straight forward. 5ml of water. Add a drop at a time and stir. Then use the chart after the solution goes from blue to green to figure out your numbers. After adding 15 tablespoons of baking soda this morning it is now reading 8. Which is not what I wanted so quickly but now I know the reference is wrong and it should have said tsp. Anyway, just wanted to throw that out to show that the testing should be accurate.

My Duncans being shriveled up for the past few weeks is what prompted me to test everything, then I found this. Today the Duncan is now much more extended. I'm thinking I got extremely lucky with such a large bump in the alk so quickly.

 

[BoxKing]

Yes, you most likely got lucky, but keep an eye on things.
The real solution here is not to add soda ash to your salt mix, but to buy a salt that mixes close to your desired level of ALK- I still feel that your figures are off from the testing bc I never saw DKH that low on any salt mix. I suggest buying a Hanna DKH - tests takes 2 minutes, and the digital readout is far better than a reference on shades of colors. You will have to do a mini science fair project every time you mix your salt if you dont get this straighten out. In the meantime, take your salt and give it a good shake/mix in the bag it came in.. maybe that will help.

Also you might want to test your CAL... you could have a severe unbalance of ALK CAL at this point, which you should address if so.

 

[c0mf0rt]

Ok, thank you. I'm starting to think my mixing is the culprit. I'll start testing as soon as I think it is complete as well.

 

[Randy Holmes-Farley Verified Community Expert]

....and to anyone who reads this in the future..... There are two answers on the web for raising the alk in the tank. 1 tsp per 10 gal or 1 tbsp per 10 gal. The tsp answer is correct. I didn't find it until later and used tbsp. My alk just went up five points! Crap, hopefully everything doesn't die!

Neither of those are exactly right for a 3 dKH rise.

3 dKH boost in 10 gallons needs 3.4 g/0.7 teaspoons of sodium bicarbonate

Always use an actual calculator:

Reef Chemistry Calculator

 

[c0mf0rt]

Thank you for the calculator, excellent tool.

I kept reading to raise the alk at no more than around 1.4 each day. Mine went up 5-6 in a matter of hours. How is everything in my tank not fried? I just did multiple measurements since dosing this morning to duplicate and got 9 multiple times.

It had to have been that low considering what I dosed. I can't believe I didn't fry everything in the tank.

.... I forgot to mention, corals look super happy today after all of this.... ?????

 

[Randy Holmes-Farley Verified Community Expert]

Thank you for the calculator, excellent tool.

I kept reading to raise the alk at no more than around 1.4 each day. Mine went up 5-6 in a matter of hours. How is everything in my tank not fried? I just did multiple measurements since dosing this morning to duplicate and got 9 multiple times.

It had to have been that low considering what I dosed. I can't believe I didn't fry everything in the tank.

I'm not sure what is in your tank, but I think it is mostly SPS corals that do not like sudden alk changes since they are using it rapidly.

 

[c0mf0rt]

That would make sense. Just about everything I have are softies or LPS. I'll keep an eye on my two SPSs.

Learning a lot today. Ordered a Hannah tester for the calcium as I didn't already have a test kit for it, I know, I know.

I'll be replacing all my stuff with Hannah devices going forward I think as I run out of my current Red Sea test kits.