Salt Water Storage Time

[Freshman]

Randy,

I have two questions, one of which is more general and the other is a chemistry guess on my part (which I hope you can clarify).

First question, I mix up 40 gallons of RO/DI water with Tropic Marin for my water changes. I have a 60 Gallon tank that I do about 10-15% water changes weekly (around 10 gallons maybe 15 but not very often) so it takes me 2-3 weeks to get though my 40 gal container. At the end of the 3 weeks my water starts to have a faint smell (bacteria?) Should I not use the water towards the end of the 40 gal or am I ok?

Second, also towards the end of the 2-3 weeks I get sediment that covers all the equipment in the 40 gal container (heater, powerhead, and airstones). My guess is Calcium precipitation? That a big guess on my part! I do have to buffer my salt mix quit a bit to get the Alkalinity (11dkh), Calcium (400), and Magnesium (1200 or around 3 times my calcium level) to the levels I like. But that might not have anything to do with the sediment.

Thanks for your help!

Brent

[Randy Holmes-Farley]

Can you describe the smell?

FWIW, I use salt water that's been sitting in a trash can for weeks sometimes.

Calcium pecipitation does sound likely, although there are also other things in salt mixes that can come out of solution (or never went in). Adding the buffer will make such precipitation more likely. Exactly what buffer do you add?

[Freshman]

Randy,

Hmmmm…not sure I can describe the smell. It’s like stale water smell or maybe the start of a rotten smell (hard to tell). I guess all I can say is it smells bad and not like it did when I mixed it fresh (not sure if that was any help).

I add Bionic 2 part to get the Alkalinity and Calcium up (11dkh and 400) and then I use Salifert magnesium to get it up to around 1200 / 1250. The Tropic Marin salt mix is very low IMO when it comes to alkalinity, calcium and magnesium.

Thanks again for you help!

Brent

[Randy Holmes-Farley]

It is probably nothing to worry much about, but keeping it stirring or otherwise aerating may prevent it from having any conversion of sulfat e to hydrogen sulfide as bacteria look to consume any organics present and anaerobically use sulfate instead of oxygen.

Using B-ionic to raise the alkalinity substantially may not be the best choice as the pH will rise a lot, increasing the liklihood of precipitating CaCO3. Use baking soda instead for that purpose.

[Freshman]

So Randy,

I should mix it up completely and once it’s all dissolved take out the airstones and powerhead (leaving in the heater)?

I also have Kent superbuffer dkh can I use that instead of the Bionic part 1 or is it the same thing (I bet it is….). If so, how much baking soda should I use to raise the alkalinity from around 7dkh to 11 dkh?

Brent

[Randy Holmes-Farley]

I just leave mine completely alone (no heat either), but if you are tryiong to prevent it becoming anaerobic, a powerhead or airstone may help (although a heater may provide enough current by convection if it is on a lot).

The baking soda is slightly better for this purpose that the superbuffer, but the superbuffer is better than the B-ionic (because of their relative pH raising effects).

From this article:

Solving Calcium and Alkalinity Problems
http://www.advancedaquarist.com/issues/nov2002/chem.htm


"To raise 50 gallons of tank water by 1 meq/L will require about 16 grams of baking soda (sodium bicarbonate; sodium hydrogencarbonate). Since a level teaspoon of baking soda weighs just under 6 grams, then 1 teaspoon will raise the alkalinity in that 50 gallons by ~0.4 meq/L (~1 dKH)."

[Freshman]

Randy,

I really appreciate your help! My reefing experience has been a lot more enjoyable due to the knowledge I get from your forum (basic understanding of Alk & Cal all the way to spiked Kalc mixes that I now use to keep my Alk & Calc up in my SPS tank). I’m still a rookie but am learning quickly thanks to your help.

Thanks again,

Brent

[thackray]

We mix salt water in two locations. One is a dark cellar in an old glass tank the other is a first story room in a translucent (milky) plastic container. Both have power heads running and heaters. The mixture is Instant Ocean only. The salt water in the dark basement has never smelled but the salt water in the well lit first story room begins to smell in as little as three days

[Randy Holmes-Farley]

Brent:

Thanks, I'm glad you've found the forum useful.

Thackray:

Maybe some cyanobacteria or other photosynthetic organisms begin to grow in it.

[Dz99ls]

Randy, while were on this topic i have had this happen and have no idea why once or twice we have mixed up saltwater in a rubbmade bin for a water change and then not been able to get to the change for a couple days the water has a heater and ph in there and we have found a brown film on the inside of the tub any idea what this could be? i also noticed above you said you have used salt water after weeks of sitting how long can you leave ro di sitting? thanks Dz

[Randy Holmes-Farley]

I leave both salt water and RO/DI sitting for weeks sometimes.

There are a variety of things that may precipitate or settle from salt mixes, with calcium carbonate being among the most likely. My salt mix trash can has a light coating of stuff.
I don't worry about it.

[Dz99ls]

thanks for your help

[Randy Holmes-Farley]

You're welcome.

Happy Reefing.

[MargaritaMan]

I mix 450g of salt water every 4-6 weeks and have done so for years. I circulate it with a P.O.C. old Rio pump. Yet to have any failures. "knock on wood" MM