DIY Automated salt water mixing system

[sphelps]

For what it's worth the last system I used the saturated approach I outline before had a 29 gallon tank for the salt tank, with the overflow installed it probably only held just over 20 gallons of water. I use to fill it with a full box of reefers best salt. So 20 kgs of salt to 20 gallons of water, never had a precipitation issue.

[Seth81]

Originally Posted by Zoaelite

Have you taken in account the calcium bicarbonate precipitation that will occur with highly elevated levels of both calcium and HCO3-?

I have a feeling your pump would kick out on you in the span of a day with that much abiotic precipitation.

Quoted from Randy Holmes-Farley here:

Most centrifugal pumps would not even blink if some precipitate was sucked in, however I agree that sucking in precipitate or any other non-dissolved salts should be avoided so the intake of the pump should be elevated. Alternatively I could have the pump external to the tank rather then submerged with the intake above the salt/precipitate level.


The article you cited is very interesting, I think it is relating more to how Ph effects saturation levels. I would think in my proposed setup, that once the saturated saltwater hits the RO water in the SW tank some amount of time and mixing would be required before the water should be used in the display tank. Which I have no problem with... I could program the SW tank to be filled with a mix of RO and SSW say a day or two before the scheduled water change.

I did find a yokogawa transmitter on ebay for $65 that accepts most standard probes.

[Seth81]

Originally Posted by SeaHorse_Fanatic

You're planning to add greater complexity and risk into the system. Imagine the disaster that would ensue if the mixing process doesn't work proeperly and you add saturated sw into your display. Salinity would spike and probably kill a lot of livestock. Just my thoughts.

Thank you for your feedback, yes I agree there is added complexity in the system. The risk of adding saturated salt water to the sump directly is mitigated by not having a direct line to the SW mixing tank. Additionally a conductivity probe added to the SW mixing tank can be used to ensure the proper mixing has occoured. Also if I had the budget I could add another conductivity probe to the sump, although this isn't really necessary.