Long Term Saltwater Storage Without Dropping DKH... Possible??

[Rahl187]

I have researched and researched and found no solution. Found no thread here specifically about this either.

So I have tried this, and as most of you surely already know, it does not work well. I even used powerhead for circulation and heated to 80 F. It seems that, that which makes up DKH, precipitates on the side of the container. My experiment was done with a standard 40 gal Brut with a lid, RO/DI water, mixed with Red Sea Coral Pro salt. Starting DKH was almost 13 and two to three weeks later it is now as low as 6 DKH. Dropped to about 10 DKH in just two days. I had the powerhead pointed straight up so as to try to avoid a static charge caused by a vortex effect. I even tried rubbing off the precipitate from the side of Brut, powerhead, and heater. That didn't help. It just turned to a sand like substance now on the bottom of Brut.

This precipitation does not seem to happen in an aquarium, so is it just the plastic that the Brut is made of?? Wouldn't it be nice if we could just mix up a couple months of saltwater to do water changes?? What are your thoughts?

 

[polleke]

I have once heard that CO2 diffuses into the water thereby lowering the KH via some reaction. Have you tried completely sealing the container?

 

[Realposition]

Red Sea recommends mixing the coral pro salt for no more than 4 hours before using it due to the exact issue you just described. It might work if you use a salt mix closer to nsw parameters

 

[Osteoclast]

I have noticed precipitation with storage of this salt long term as well. It appears to be accelerated by temperature. I get the same precipitation Rahl187 describes (and I have witnessed it also with other mixes) that is probably just abiotic precipitation. This material is hard, crusty, flakes off, and forms sand as described. This has been described by RHF and others and is common.

But I have also observed a coating/residue along the sides of my storage container that is brownish in coloration when the salt water is left for weeks at a time. It is a thin film that can be brushed off and does not appear to form sand grains. I suspect it is due to the organics and vitamins in the mix. I have my 170 gallon mixing container covered and shielded from light in my basement so the coating may be bacterial but that is my guess. Red Sea recommends mixing and using within 4 hours so I have stopped storing this particular salt and try to use it within 24 hours or less after the initial mixing.

From my reading there are a few other salts available that appear to store better for longer.

 

[snorvich]

I store RO water (couple hundred gallons) but mix salt water as needed. Just could not solve the problem everyone has encountered. (I use ESV salt).

 

[silentscream]

I store RO water (couple hundred gallons) but mix salt water as needed. Just could not solve the problem everyone has encountered. (I use ESV salt).

Even with ESV salt you have found the alkalinity to drop over time?

 

[snorvich]

Even with ESV salt you have found the alkalinity to drop over time?

While I do not store made up salt water, with ESV salt water in my tanks, alkalinity drops from about 10 to 9+ over a two week time.

 

[dkeller_nc]

While it's probably impossible to completely prevent the precipitation of calcium carbonate in new salt water as its stored without adding a bunch of organic chelators (undesirable, IMO), lowering the temperature and keeping the vat quiescent does help.

Calcium is an odd beast in that it's more soluble at colder water temperatures, which is the opposite of most other ionic substances. I've been able to keep Instant Ocean stable at about 9 dKH for a couple of weeks if I mix it up for 4 or 5 hours without heating then turn off the powerhead and store it at my basement's ambient temperature (about 60 deg F in the winter, 68 deg F in the summer).

 

[ChrisKirkland]

I also store several hundred gallons of RO/DI water and mix saltwater on demand. I have 1 heated container of RODI water I use for top off.

 

[Rahl187]

Yes, my Brut has a good lid on it. It snaps tight but may not seal perfectly.

A guy at BRS said to try putting a bag of crushed coral in the mix. I understand that the aragonite in the aquarium is supposed to help buffer but is that the sole reason DKH does not drop so rapidly in an aquarium?

I will just go back to mixing on demand. However, this should be theoretically possible since a precipitate does not seem to build up in an aquarium.

Next step would be to try putting a bag of aragonite or crushed coral in with the mix. I will try to do this experiment soon but if anybody else gets to it first please post here.

 

[patiof]

Wish I saw this thread sooner. Between again my saltwater too long and using some clumped salt, it took my a couple months to figure what was happening with my alkalinity.

 

[patiof]

along those lines, does anyone see a problem with bringing the alkalinity of saltwater made a few weeks ago back up with a soda ash (sodium carbonate solution)?

 

[Rahl187]

Sure, you could dose your Alk back up, but that begs the question, what else was lost from the mix? As far as soda ash, I have not used that. I use B-ionic 2 part.

 

[patiof]

hmmm. i'll check ca and mg too, but that's about as far as my test kits will go...

 

[jonwright]

Why would it drop sitting in a tub but not in the display tank?

 

[outssider]

it does drop in a display tank, that's what dosing is all about. kind of hard to tell how much of the dosing is animals sucking out the calcium carbonate and how much is just some precipitation. I've been dosing since practically the very first day of set up. now it's just way way more than the first few weeks.

 

[jonwright]

The rest of that is: we assume the metabolic processes of the tank consume alk. If it drops on its own in a container that seems to me to call into questions at we've assumed is going on.

But still, again, if the metabolic (and other life) processes are not present in the storage container why would the alk decrease? Not that it's a point over a month. Seems rather significant over a short period of time.

 

[Useful_Idiot]

Does natural seawater have the same alkalinity drop when stored? I assume it would, just curious if anyone knows.

 

[JJshiv]

I use NSW and have not noticed an alk drop like described. If it does, then it is no where near as dramatic. I store it for up to a month at times.

 

[patiof]

so i dosed my week and a half old sw made from reef crystals (they salt was largely clumped) sitting in a 20 gallon brute back up to around 10dkh on saturday with brs soda ash solution. checked it the next day and it was back down under 6 again, which was where it was at before i dosed it. fml.