Continuous Water Changes

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drcrook

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I'm setting up a water mixing station in my garage. I'll have RO/DI & Salt Mix. I'm going to ATO & Auto Change from there. I'm building out approximately a 265 gallon system. I wanted to make sure I only have to mix salt water once per month at most, so trying to figure out appropriate sizing for my reservoirs for ATO & Salt Mix.

About how many gallons/day should I be looking to continuously change? My math says 20% water change monthly = 1.7 gallons; I'll probably do 1.5 gallons/daily, 30 days, add 20% for safety and a 55 gallon reservoir should be good.

Anybody have thoughts? I'll be running a refugium, skimmer and 2 part dosing. Primarily SPS & fish in the tank.

Does the 1.5 gallon/day make sense? Is there a different advise than 20% monthly when doing continuous water changes?
 
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Peace River

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The Reef News Network hosts (Peter and Jeremy) have talked about this on their podcast. I don't remember the exact amount that Peter uses but the amount that you listed sounds about right. Congratulations on the new mixing station!
 

zalick

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Seems the majority do 1% per day. When I get mine setup, I’ll be doing that as well for a ~370g total volume system.

as for containers: get the largest you can fit in the space AND can access the inside. I opted for two 100g tanks from norwesco.
 

Azedenkae

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I'm setting up a water mixing station in my garage. I'll have RO/DI & Salt Mix. I'm going to ATO & Auto Change from there. I'm building out approximately a 265 gallon system. I wanted to make sure I only have to mix salt water once per month at most, so trying to figure out appropriate sizing for my reservoirs for ATO & Salt Mix.

About how many gallons/day should I be looking to continuously change? My math says 20% water change monthly = 1.7 gallons; I'll probably do 1.5 gallons/daily, 30 days, add 20% for safety and a 55 gallon reservoir should be good.

Anybody have thoughts? I'll be running a refugium, skimmer and 2 part dosing. Primarily SPS & fish in the tank.

Does the 1.5 gallon/day make sense? Is there a different advise than 20% monthly when doing continuous water changes?
Depends on how you look at it. If the calculation is just 20% of 265 divided by 30 days or thereabouts, yes around 1.7 gallons (or 1.76 gallons rather) per day makes sense. However, don't forget that multiple smaller water changes are not as effective as one larger water change, presuming concentrations of whatever does not increase/decrease aside from the water changes. So a 20% water change a month means you keep 80% of what you currently have in your tank. To get the same result from daily water changes, you need to change closer to 2 gallons a day. It is not exactly so because the assumption that nothing changes is wrong, as for example corals would consume calcium, carbonate, trace elements, etc. But yeah, I'd do more like 2 gallons a day rather than 1.5 gallons.
 
Fritz

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What type of equipment will you be utilizing for auto changes?

As Azedenkae noted, if you’re using something like the Neptune DOS, you typically remove and replace simultaneously, thus not a true “water change” but instead more of a dilution. In my 200g system I’m performing 4-5g per day through DOS and as much as 8g per day mainly to experiment with trace mineral replacement using Red Sea blue bucket Salt. I’ve found 2+ gallons for me reduced no3 and po4 so plan accordingly if you seek stability in those areas. In fact, at above 5g per day my no3 dropped to below 2 (I shoot for 5-10) which caused me to dose a few mils of sodium nitrate to new incoming saltwater.

Good luck with your project
 

AJsReef

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I do a continuous water change of 1%/2g per day. IME it’s more than sufficient to keep trace elements in line for my system. It’s worked great for me over the past 3+ years.

Personally, I’m a big fan of fail safes. I have an optical sensor to sense when the new saltwater tank is low to cut my AWC pumps or if salinity drifts too much.
 
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drcrook

drcrook

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For automation, my plan was to
1. refill the RO/DI water via ato kit
2. top off the salt water manually with RO/DI & Salt, but add a salinity sensor into the new saltwater tank. I would end up doing this the same day as yard work so I can mix, cut the grass & weedwack, adjust params if necessary.
 
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