I think it's a very cool idea. Has anyone considered the amount of new water they are taking out while adding new water. I know in very small amounts but it does happen. I would think that if you had a sump big enough I would prefer say take out two metered gallons then put in two metered gallons but not at the same time. I would have to do 3.5 gallons daily for myself.
After a whole year how much new water are you taking out while adding. I really like the take out then put in method myself but think it would be really cool to automate it with an apex. I gues you would need two pump setups then.
This was my concern as well. Since I will have an arduino running it I am trying to figure out if I should have two motors running and have the arduino shut off various devices like return pump, ato and skimmer, remove water then pump the new stuff in. So it is automated water change, not continuous. I also don't really like having saltwater stored.
It never made sense to me that red sea pro salt says to use in an hour or so after mixing. Does this mean that in the next couple hours if my corals don't use the trace elements they will be useless?..
The pumps are made to be stacked together, no mods were made other the the screws needed to be longer.
Thank you! Great pictures!