Help me plumb a 125g for auto/semi auto water changes

[Greg5OH]

This is actually for my 125g discus tank, but I figure nobody has as advanced tank plumbing as reefers do. Doing 50% WC every 2 days with a hose and tap gets tiring..I want to make it so I have to turn a few knobs or have it automatic.
I fill my tank straight from the tap (well water). just adjust my tap to 84F out and I have a septic system. No need for aging barrels or ATO etc.



Tank is 6' long and it shares the back wall with my bathroom. it is not drilled.
I have a hot and cold water pipe right behind it and the wastewater drain from toilet and upstairs kitchen on the other side. The PVC wastewater drain already has a cleanout tap on it so would be easy to get into. The freshwater hot and cold are copper pipes and would just need to be cut and tapped into.

Two things I am looking for
-automatic temperature regulation of the fill water
-automatic shut off of fresh water to prevent over filling

I dont think i need to drill the tank for this since Im not running a sump, just one drain pipe over the side , terminating at 50% height, with a pump to initiate a siphon, some type of backflow valve on the drain to prevent sewage from ever entering (even run 2?) and some kind of temp regulating valve with an ATO style water shut off sensor?

walk me through this. I want it fool proof and redundant safety systems.

Thanks in advance!

 

[Greg5OH]

Im thinking I can set this up with a neptune system. Not a DOS.
Essentially use (12 volt?) solenoid valves, and the neptune would control them.

I assume I can set up some safeties in it,
for example:
Drain sequence:
See that water is "full"
open drain valve,
start drain pump (located in the tank)
turn off drain pump when low level sensor tripped
close drain solenoid valve

Fill tank:
see that full sensor shows level low
see the drain solenoid is closed
open fill solenoid valve (water temp preset at the outlet)
turn off fill solenoid when full sensor shows full.

I would have a manual ball valve on the fills just in case the solenoids fail, I can shut the water flow off in an emergency.

I would also like to run a redunant safety sensor on the fill.

 

[tkeracer619]

What I've done in the past in sumps but could be done easily in this setup is to drill the tank and install an overflow stand pipe, connect it to a drain through a p-trap and a break (to prevent backflow if the sewer backs up)

As you add water to the tank it overflows into that drain.

You don't want to connect hot and cold together behind a solenoid because when you turn water on somewhere else it can mix hot and cold throughout the house.

You will want to get a "3-Way Thermostatic Mixing Valve". This will let you set the temperature. Some of them will prevent flow if cold water isn't available to prevent scalding (nuking your tank). Use a solenoid valve to control flow. (I would consider running two in series, just in case)

Consider a reef controller that allows temperature monitoring so that if something goes wrong, it shuts the system down. Consider installing a time delay relay between the controller and the solenoids in case the controller fails on, you can set the max on time through the relay.

If you are familiar with arduino you could easily create a controller to do what you want pretty cheaply.

 

[Greg5OH]

thank you that does sound pretty good. Im assuming the neptune can handle shutting it all down if something is wrong (too high or low of temp?)

The 3 way mixing valve sounds like the ticket for filling the tank and making sure it continues getting filled at the proper temperature.

regarding the break, thats just a check valve essentially yes?

Im not opposed of drilling and putting in an overflow, however I would need a solenoid valve on the end of the drain which needs to open first before allowing the system to fill (since its not an overflow system, the drain would be submerged in water)

The time delay relay is a good idea.

Im not handy with programming and I dont have the time to teach myself and debug the system, so I dont mind paying for a robust system. Assuming the Apex or similar can do this task.

 

[tkeracer619]

thank you that does sound pretty good. Im assuming the neptune can handle shutting it all down if something is wrong (too high or low of temp?)

The 3 way mixing valve sounds like the ticket for filling the tank and making sure it continues getting filled at the proper temperature.

regarding the break, thats just a check valve essentially yes?

Im not opposed of drilling and putting in an overflow, however I would need a solenoid valve on the end of the drain which needs to open first before allowing the system to fill (since its not an overflow system, the drain would be submerged in water)

The time delay relay is a good idea.

Im not handy with programming and I dont have the time to teach myself and debug the system, so I dont mind paying for a robust system. Assuming the Apex or similar can do this task.

Yup, the Apex will do that stuff and more.

Regarding the break, it can be done several different ways, traditionally you would want a sewer backflow preventer but I don't personally think they are full proof. What I typically do is basically make an elevated floor drain and the plumb the overflow drain into that but leave an air gap. This makes sure the tank isn't directly connected to the sewer and if it does back up it cannot make it into the tank.

You don't need a solenoid valve on the tank, you run a standpipe that is just above the normal operating level. As soon as you start filling it will overflow into the stand pipe and go down the drain. I've done this a few times on big setups. It works great!