RODI / Mixed Saltwater Storage

[Adalius]

So I'm looking into buying some tanks, probably Norwesco, for holding my RODI and mixed saltwater stores. I'm going to be using the RODI for general use and ATO, and the saltwater will be doing auto-water changes with the Dos, I'm figuring about 1.25 gallons a day as that works out to a 10% change every 2 weeks.

So the question I have is, what size tanks should I get? I scoured the search and didn't really see any posts directed at this specifically. I know there's going to be a heavy amount of opinion, probably some 'get as big as you can manage to fit in your space' options as well, but whats everyone's thoughts on this? Obviously initial tank startup is a concern, but IMO that hardly justifies buying large tanks just for maintenance use afterwards (especially when you can always mix the initial load in a Brute)...

Is there a 'rule of thumb' or anything that you should have 'x' gallons of storage on-hand for 'y' gallons of combined system volume? Should there be?

 

[mygsris2slo4u]

As large as possible I would say, though I purchased my 55 gallon ace rotomold tanks for a few specific reasons.

1. I was able to get them via free shipping from rural king. Anything larger would require freight and skyrocket the price.
2. With a few residual gallons I add 45 gallons and one complete bag of instant ocean from the 200 gallon box and it comes out at 1.025-1.026 every time. No more measuring and/or multiple tests. This also allows for consistent batches since there’s no settling.

 

[Adalius]

2. With a few residual gallons I add 45 gallons and one complete bag of instant ocean from the 200 gallon box and it comes out at 1.025-1.026 every time. No more measuring and/or multiple tests. This also allows for consistent batches since there’s no settling.

Now see that? Right there? THATS a pro-tip and a game changer for why to pick a size.

 

[Dom]

Some time ago, the subject of storing of mixed salt water came up in a thread. The consensus was that you shouldn't store salt water, and that you should mix it about a day before you intend to use it.

I never considered automatic water changes. This would have been a good example to have someone arguing against storing salt water to explain.

How many gallons of stored salt water would you be making?

 

[Adalius]

I've heard that argument (about storing salt), and I kind of turn my nose up at it, because I used to store mixed salt in a Brute tub (45 gallons would last me 10 water changes, which was 20 weeks worth) when I had my Biocube 29 and never had any undue readings on the salt or anything ever. I did leave a very small powerhead running in it full time and would drop a heater in the day prior to using it to raise it from the household 70 degrees to the desired temp prior to grabbing out my 5 gallons. I think if you didn't leave the powerhead you might run into some precipitate issues, but with it I never had any.

So the 'how much am I making' is sort of the 'which came first the chicken or the egg' thought I'm having. The bigger the tank I get, the more I can store and less often I have to do it, however the bigger I go, the bigger the powerhead needs to be to keep it circulating so do I want to run a MP10 full time in a 65 gallon tower, just as an example (not even sure if thats sized right), or a small little fountain pump in a 20 gallon tank.

If I went with a 55 gallon (and used 45 gallons of it), which as mygsris2slo4u pointed out above is about the largest I can get with free shipping from most vendors, I'd be having to mix salt every 36 days, which isn't bad. If I went with a 30 gallon and used 25, I'd need to refill it every 3 weeks. If I went crazy and got 110 gallon units, which would cost about $100-120 ea just to ship, I could hold almost enough salt water for 3 months of water changes.

I'm just having a real hard time determining what is practical. Obviously when I mix my initial 175 gallons, the 110 gallon tanks would make it super easy (and I'd still have enough left over for a month or so of water changes after the filling of the tank was done). If I go smaller, I still have to mix multiple batches to fill it initially. None of that really concerns me since it's a one-time thing, it's more the practicality of long-term ease. How often do I really want to mix salt and how big of a tank is practical.

I guess what I'm looking for is do people with 150-200 gallon tanks have 30/55/110 gallon polytanks and wish they went bigger / could get by with smaller type input.

 

[ccombs]

These are the threads that really interest me, looking forward to some opinions. By trade I deal with a lot of logistics and system planning, so thinking about it in relation to my hobby is fun

 

[Adalius]

Some time ago, the subject of storing of mixed salt water came up in a thread. The consensus was that you shouldn't store salt water, and that you should mix it about a day before you intend to use it.

I thought I'd come back to this since BRStv just released an episode where they mixed salt and tested it for up to 4 weeks to see if it had any issues with being stored. Very interesting results. With the exception of one brand of salt mix, there was very negligible changes in the stored saltwater after an entire month. The one key thing to note, though, is that they stopped mixing once clear, and did not circulate or heat the water at all from that point forward.

Here's the video:

 

[Dom]

Great video; thank you for posting. I would like to have seen them take it out further...