Maintaining alkalinity levels

[Jim Barry]

I have been having trouble maintaining my alk levels in my tank recently. My calcium reactor is supplying suffient calcium.

My readings are;

Alkalinilty: 5.4 dkh
Calcium: 400 ppm
Magnesium 1500 ppm (minimum).... that was the highest reading available on my salifert test kit

spec gravity: 1.024
ph in tank: 8.08
ph in calcium reactor effluent: 6.5-6.7

Is this level of alk too low?

Is there anything I can do with my calcium reactor to raise the alk to 8 dkh without raising the calcium any higher?

Also, how often should you change the ARM media. I read that it should deplete, however after 6 months I still have pretty much the same amount in the reactor.

Thanks for your help

Jim

[Bryan]

Test the alk of your reactor effluent. Should be approx 3x times of your desired tank levels. This would be a start to see if your reactor is tuned optimally.

[pocilipora]

Id aim for an Alk around 11dkh or 12dkh, not any highter than that. As for the calcium, wouldnt worry about it at all. I personally only test for Alkalinity, I think its more important.
The Arm will slowly disolve over a long period of time. Just depends on how your reactor is set as to how long that will take.JMO

[Delphinus]

The calcium reads 400 which by itself sounds "not bad" but because of the lower Alk, "nobody's using it." So raising your effluent rate from the reactor may initially bump the Ca up as well, but as the Alk raises the consumption rate for the Ca will also rise, thus the Ca will come down and stabilize.

What your readings tell me is that your effluent rate can be increased (the CO2 will need to be adjusted appropriately). I aim for a pH of 6.7 in the reactor, that translates roughly into equivalent of "effluent has an alk 3x of your desired tank levels".

That said, since your Ca&Alk parameters are slightly off balance, you may be better off in the short term to use a 2-part to acheive that balance (in addition to increasing your reactor's output). Reason being that the reactor should be used to maintain the levels rather than "raising them from point X to point Y."

[danny zubot]

I have question for anyone who knows.

I found a recipe for making washing soda out of baking soda, some of you may be aware of it. The washing soda will raise the alkalinity of your water which is adverse from baking soda which will lower it. To maintain the existing alk and increase the buffering capacity of the tank you can add a mixed ratio of washing to baking soda solution to achieve a neutral solution (8.1-8.3). Does anyone know what the ratio is?

[marie]

Originally Posted by danny zubot

I have question for anyone who knows.

I found a recipe for making washing soda out of baking soda, some of you may be aware of it. The washing soda will raise the alkalinity of your water which is adverse from baking soda which will lower it. To maintain the existing alk and increase the buffering capacity of the tank you can add a mixed ratio of washing to baking soda solution to achieve a neutral solution (8.1-8.3). Does anyone know what the ratio is?

Baking soda doesn't lower alk it lowers ph. Do a search on Randy's forum on RC the info is there somewhere

[Canadian Man]

And the effect on ph is only for a minute or so. I tried the washing soda/baking soda thing and found that the washing soda step was not needed. It also failed to dissolve so it was basically useless.

If I have to make an alkalinity adj now I just use baking soda all by itself and add it slowly.

[danny zubot]

So let me get this straight; washing soda only raised your PH for a short while? what about the alk? I'm confused now

[marie]

Both washing soda and baking soda will raise you alk., washing soda will raise your ph. as well, while baking soda will temp. lower your ph. not by a large amount though. Using the two together will have a neutral effect on ph. thats the theory anyway . Any time i need to raise just my alk. i just use baking soda

[sleeman]

Does anyone have te formula handy? I remember reading it in a book somewhere, but don't have the time to track it down.

Cheers,
Al