RO/DI Top Off Water and Alkalinity

[PatMayo]

Randy I have several questions for you if you don't mind?

I store my RO/DI top off water in a 44 gallon brute can. I don't areate the water before use. I don't add much to my system, about 3/4 of a gallon per day. I try to add half in the am and the other half in the pm in my 110 system.(including sump)

The RO/DI water is zero tds. It has zero alkalinity in the water as well. Would it be beneficial to add your alkalinity formula to the RO/DI water in the storage container? (I use formula 1) Wouldn't this result in less addition of your formula everyday to keep the alk correct?

I am surmising that adding this stripped out pure water is what causes a good portion of the alklinity loss. I only have 2 fish and coralline growing.

My other question is will it harm the water bringing the alkalinity to normal levels and then storing it for some time? 44 gallons lasts quite a while since I don't evap that much.

And If I can do that for the alkalinity would it work for the calcium as well?

Regards,

Pat

 

[Randy Holmes-Farley]

The RO/DI water is zero tds. It has zero alkalinity in the water as well. Would it be beneficial to add your alkalinity formula to the RO/DI water in the storage container? (I use formula 1) Wouldn't this result in less addition of your formula everyday to keep the alk correct?


It would certainly be fine to add the alkalinity supplement in the top off water, but it isn't necessary or "better". But it might make less work for you.

I am surmising that adding this stripped out pure water is what causes a good portion of the alklinity loss. I only have 2 fish and coralline growing.

Water that evaporates contains no alkalinity, so adding top off water with none is an alkalinity neutral process. It is not a cause of reduced alkalinity.

My other question is will it harm the water bringing the alkalinity to normal levels and then storing it for some time? 44 gallons lasts quite a while since I don't evap that much.

Using baking soda that way is fine. It won't degrade.

And If I can do that for the alkalinity would it work for the calcium as well?

Yes, in a separate container. You cannot mix them.

 

[PatMayo]

I understand.

Thank you very much.

Regards,

Pat

 

[Randy Holmes-Farley]

You're welcome.

Happy Reefing.

 

[old salty]

Pat,

I hope you don't mind my adding to your thread as I have a few questions that are pretty much in addition to the ones you have just asked.


Dr. Farley,

Like Pat, I drip saturated limewater (well, I think it's saturated; I add 1 cup of lime per 44 gallons of water and stir it for about 2 hours.) Just over 2 gallons of evaporation occurs daily. The alkalinity in my tank seems to want to stabilize at 7.4 dKH. I used your reef calculator and made a concoction of 4 teaspoons of baking soda and 1 gallon of RO/DI water to raise the dKH to 9.5 or so. This keeps coming back down for some reason (to 7.4 where it stabilizes) even though I am topping off with limewater. The calcium maintains a very steady 430-440 range and pH is about 8.3. Just the alkalinity falls off.

If I understood you correctly, adding some baking soda to the limewater which I use to top off will provide some additional alkalinity with no side effects. Does the dropping of alkalinity without the dropping in calcium seem odd considering the use of limewater for topoff? I have about 20 small SPS frags and some fish; nothing that would make me believe that the tank has a huge appetite for alkalinity consumption.

 

[Randy Holmes-Farley]

No. You cannot add any baking soda to limewater. It will just precipitate calcium carbonate.

Does the dropping of alkalinity without the dropping in calcium seem odd considering the use of limewater for topoff?

No that is the illusion (not a real effect) that happens when dosing of both is inadequate because there is a ton of calcium and not much alkalinity in seawater:

When Do Calcium and Alkalinity Demand Not Exactly Balance?
http://reefkeeping.com/issues/2004-12/rhf/index.htm

 

[old salty]

Just when I thought I had read every single one of your articles, you present one that has EXACTLY what I was describing!!!

As usual, your services are greatly appreciated!!

 

[Randy Holmes-Farley]

:lol:

You're welcome.

Good luck.