Saltwater mixing station design

[Willbiker]

Hi All

I find mixing water the biggest chore of the hobby and I want to build a mixing station that will hold lots of premixed saltwater (4 changes worth for me) so I have drawn up the following diagram and was hoping you could point out any flaws in it. I will be using 3x 200l food grade HDPE barrels (the blue ones). Two for mixing/storing and one for RO. This design allows me to mix up 400 litres of salt water in one go but also isolate one of the barrels so i'm not heating all 400 litres before pumping out to the DT. Here it is.

Scenarios:
Filling and mixing
Filling both mixing drums - RO valve and valve 3 and 4 are opened allowing both bottom drums to fill
Mixing - valves 1,2,3 and 4 are open and pump pulls from both drums and returns to both drums, Salt added

Water change 1 of 4
Heating - Valve 2 and 4 are shut circulating the left drum only, heat applied
Output to DT - valve 3 and output valve open, all other valves shut. 1/2 the drum is pumped to tank

Water change 2 of 4
same as above step however remaining half of the left drum is pumped to DT

Water change 3 of 4
Refilling left drum - valve 3 & 2 is shut, valve 4&1 open, 1/2 of right drum is pumped to left drum.
Heating - Valve 2 and 4 are shut circulating the left drum only, heat applied
Output to DT - valve 3 and output valve open, all other valves shut. left drum pumped to tank

Water change 4 of 4
Same as water change 3 above

Now both mixing drums are empty and the process can repeat. The top RO tank will be filled after mixing has started to be available for top offs.

What do you think? My only concern is when doing the initial salt mix, will the water circulate effectively between both barrels??

 

[Peace River]

As you finalize your mixing station plans you may find this thread helpful and even find a few tips:

Let’s Mix it Up! Designing and Using a Water Mixing Station

Let’s Mix it Up! Designing and Using a Water Mixing Station Let’s Mix it Up! There is one undeniable fact in this hobby – WE ALL NEED WATER! In fact, two types of water. Clean fresh water (FW) run through a quality RODI system and the obvious saltwater (SW). Secondly, we all know what a...

www.reef2reef.com

Good luck!

 

[Bryn]

@Peace River has a great link. From your diagram I do not see anything glaringly obvious.

 

[CK00020]

I would only mix one drum at a time, but if you have a big enough pump give it a try

 

[Willbiker]

Thank for the link and the replies. I will have a 6000lph variable speed pump which should give enough oomph to pull from both drums. I shall try it and see how it goes!

 

[Willbiker]

For the benefit of anyone looking at this thread who intends to build a mixing station, I went ahead with this design and it works well! I decided to go with an inline heater instead of a submersible one meaning I can heat either side or both together if I choose to! I also added some switches to easily turn the pump and heater on/off.

The only imperfection with the build is I didnt plumb the pump completely central between the two bottom feeds so one pulls slightly more than the other. This just means that the water level sits about 1 or 2 inches higher in one barrel than the other when mixing both together which I can live with. Anyone who plans to build this, make sure the plumbing is symmetrical and go for a pump preferably larger than 6000lph. However 6000lph seems enough. It looks scruffy as I used materials which I had laying around but here is an picture! Very pleased!

Next improvement will be a float switch for auto shut off when filling!