Why do most people have two water reservoirs?

jgvergo · Nov 14, 2015

I'm planning my fist saltwater tank and I've done a lot of reading about RO/DI and water mixing stations. I will be using RO/DI but I have limited space and setting up two separate reservoirs for the RO/DI water and the mixed water is going to be tough. What is the down side of having my DO/DI go directly into my mixing reservoir?

Joshky · Nov 14, 2015

Not everyone has a reservoir, some people simply make water when needed. Reservoirs are a luxury, having two isn't necessary at all just a nice commodity.

jgvergo · Nov 14, 2015

Joshky said:
Not everyone has a reservoir, some people simply make water when needed. Reservoirs are a luxury, having two isn't necessary at all just a nice commodity.

That makes sense Joshky, but let me ask it another way. What is the advantage of having two reservoirs over having "only" one

steve&mari · Nov 14, 2015

You can always have both ro/di and sw ready incase of a emergency need.

Jlobes · Nov 14, 2015

having two smaller reservoirs is great. it allows you to store quite a bit of RODI, but also most are plumbed in a way that one can be mixing salt water, and the other storing fresh water. So, you can have both salt and fresh rodi on hand at any given time

not necessary by any means, but definitely makes things easy, and we all the the easier things are, the more often they get done.

Lynn52 · Nov 14, 2015

I use one for RODI and the other for salt water.

bobman · Nov 14, 2015

Wrong thread Lynn lol

Lynn52 · Nov 14, 2015

Yep I caught it right after I hit post.

bobman · Nov 14, 2015

I would be lying if I said I have not been guilty of it a time or 2

pgravis · Nov 14, 2015

If you are just going to use one reservoir, for top off water and mixing salt for water changes, make sure you give it a good rinse between the two tasks, otherwise your salinity could creep up.

jgvergo · Nov 14, 2015

pgravis said:
If you are just going to use one reservoir, for top off water and mixing salt for water changes, make sure you give it a good rinse between the two tasks, otherwise your salinity could creep up.

If I only use one reservoir, I will measure the salinity before I do a water change. I intend to keep my water parameters as perfect as possible.

bobman · Nov 14, 2015

pgravis was more referring to fresh water. As for top off water after you mix salt in the reservoir there will be some salt left so when you fill it with fresh water there will still be a small amount of salt and could raise your salinity over time. Not really a big deal IMO but something to keep an eye on.

jgvergo · Nov 14, 2015

jgvergo said:
If I only use one reservoir, I will measure the salinity before I do a water change. I intend to keep my water parameters as perfect as possible.

Ah, I understand. The bottom line is that the DT salinity needs to be kept constant at 1.025

bobman · Nov 14, 2015

Correct 1.025 is a good spot to be for most anything you wish to keep. Assuming you are going reef tank that is.

jgvergo · Nov 14, 2015

bobman said:
Correct 1.025 is a good spot to be for most anything you wish to keep. Assuming you are going reef tank that is.

Corals are my primary objective with the tank.

steve&mari · Nov 14, 2015

We actually use 3 barrels, 1 for ro/di, 1 for mixing sw, 1 for waste h2o by the washer. We always have ro/di and sw on hand with our wastewater used for laundry. Allows for automatic water changes by controller also. With the ato also fed by ro/di our system is very stable from fluctuations of salinity ect.

Blue Lip · Nov 14, 2015

Rodi water takes time to make. It is a good idea to have a stored supply for things like top off water & mixing powder additives. Freshly made saltwater should be aged 24 hours.

Jlobes · Nov 14, 2015

Blue Lip said:
Rodi water takes time to make. It is a good idea to have a stored supply for things like top off water & mixing powder additives. Freshly made saltwater should be aged 24 hours.

agreed, aside from the storing/aging part. Not all water need/should/can be stored. RSCP says on the label, to use within 4 hours of mixing.

pgravis · Nov 15, 2015

bobman said:
pgravis was more referring to fresh water. As for top off water after you mix salt in the reservoir there will be some salt left so when you fill it with fresh water there will still be a small amount of salt and could raise your salinity over time. Not really a big deal IMO but something to keep an eye on.

Yeah, not a huge issue, just something to keep in mind if you have a multi-purpose reservoir.

ss95003 · Nov 16, 2015

jgvergo said:
That makes sense Joshky, but let me ask it another way. What is the advantage of having two reservoirs over having "only" one

I have a 55 gallon drum I keep full or refill when It gets low. I do not want to plumb that into my tank as one it's to far away but even if it were right next to my tank I wouldn't do it. If something when wrong I would not want 55g of fresh water entering into my system. 5 gallons would not cause any major issues.