90 gallon fowlr

[brokeaquarist]

debating trying to put together an auto water change system

so for example

all 3 pumps will be on seperate timed outlets.
ones i have i can set for any day of the week, on and off time (obviously)

so if i set pump 1 (return pump) timer to turn pump off for 35 mins

pump 2 timer to turn on for 15 mins 5 minutes after pump 1 turns off (herbie over flow, box takes about 5 mins to fully drain once power out)

pump 3 turn on 15 mins when pump 2 turns off.

then pump one turns back on once pump 3 turns off.

those times are just random example times. ill have to actually spend a while dialing the times in perfect.

any thoughts or advice? plan is to use maxi jets (not sure size yet) and just tubeing.

now my second thought is, haveing my waste pump in my return chamber will only allow me to pump out 10-12 gallons of water before that chamber is dry. so then if i made my pre mixed tank and water tank to hold 25-30 gallons, i could set it up to do 2 water changes a week. right?

equaling approx 25 gal wc a week, 100 gal a month. plenty for my system?

hmmm

[daplatapus]

I read a lot on auto water changes before I decided on mine. What you have posted is doable, but would have to be monitored extremely closely. Which IMO, defeats the whole purpose of an auto change system. Take for example a couple scenario's which could potentially go wrong.
1) your waste water pump isn't EXACTLY pumping the same as your new SW pump. This will cause your salinity to drift. Either by taking too much out, making your ATO pump just fresh water in, or taking out too little, and filling your sump higher than normal. This could potentially mess with your skimmer.
Film buildup, or a myriad other factors could potentially cause one pump to no longer equal the other.
2) your away at work, vacation, etc. one pump fails, or for some other reason doesn't turn on.