OK, time for a (long overdue) update: it's all set up!
Now that the tank stand
is complete and in the living room, it's time to move the autoWC system in there, too. It's been running in the shop for several weeks, hooked up to garden hoses for supply/drain.
First off, the design has been modified a bit:
With this modification, all the autoWC plumbing at the tank is done on the outlet side of the filter. This makes things a bit simpler, as the inlet side is unchanged. In addition, with this change, all the solenoid valves have filtered water running through them. This reduces the chance that one of them will get clogged, or stuck open from a dirt particle. Also, I added check valves at some of the solenoid outputs. Diaphragm solenoid valves will open with any reverse pressure. Valves 1 and 2 are such valves, so the check valves prevent this. Valve 4 is a direct-acting valve, but it has a check valve on it to help ensure that drain water doesn’t feed back into the fresh water supply.
Here’s what the plumbing looks like under the tank:
With the filter removed to make things easier to see:
Valves 1,2,3 are from the “valves4projects” Ebay site. They’re unusual for diaphragm valves in that they’ll work at low pressure, down to 0 psi. The inexpensive lawn sprinkler valves need house water pressure (~40-60 psi) in order to function, so they’re not suitable for most aquarium applications. The “valve4projects” valves are great for the price, with high Cv values (i.e., low flow-restrictions).
Valve 4 is a bit more expensive direct-acting valve. This valve needs to withstand house water pressure long-term and is important to the reliability of the system, so I felt it was worth it to spend a little more. As a direct-acting valve, it has a lower Cv value, but it has the benefit of house water pressure to push water through it.
Valve 4 operates off of 24VAC and the oher three use 12VDC; the power center I put together supplies these voltages as well as supplying 120VAC outlets for other equipment:
Here’s the AutoWC Controller box on the left side of the stand; I still need to clean up the cabling a bit:
I ended up using ¾” tubing in the run from the living room to the laundry room for maximum flow. I used CPVC tubing for long straight runs, and PEX tubing where more flexibility was needed.
For the hole in the living room wall I needed a large hole so I’d have clearance to drill through the bottom plate of the wall, but I wanted it to look neat for maximum spousal approval. I ended up installing an access panel (I later drilled a hole in the cover for the hose that connected to the tank stand):
This gave plenty of clearance for the drill:
Here’s a shot from inside the wall, showing the hole in the bottom plate and access to the joist space below:
The PEX tubing from upstairs transitions to CPVC with a Sharkbite connector, which is a great system. The Sharkbites are approved for house plumbing and in-wall use (as are PEX and CPVC), and they hook up to any potable water tubing using the CTS size system (copper, PEX, CPVC). Note they don’t work with Schedule 40/80 PVC pipes, which aren’t rated for potable house plumbing.
After this connection was made, I put the square of drywall back into place; a little spackle, some spray-on texture, and touch-up paint made it disappear.
The long run of ¾” CPVC through a utility room, which will be covered with some molding:
Making it to the laundry room, a cabinet was temporarily removed in order to make an access hole to continue running the tubing:
Here’s the plumbing at the laundry room end. Note the strainer, which guards against a dirt particle getting to Valve 4 and clogging it.
The connections to the cold and hot water supply lines are full-flow ½” lines, in order to allow a fast refill rate. Sharkbite connectors make it easy to connect the pre-assembled module to the plumbing:
Here’s the mixing valve, which does a good job of keeping the temperature at 84-85 degrees. At the beginning of a fill cycle, valves 3 & 4 are turned on for 30 seconds with valves 1 & 2 off, in order to warm up the water before sending it into the tank. Check valves on the hot and cold lines ensure that the cold supply won’t empty the water heater of hot water, or allow hot water to flow into the cold supply:
The connection to the ¾” line from the tank is also done with a Sharkbite.
Some pics of the level sensor switches. The first shows one when the tank is not full:
The next shows it when the tank is filled up:
This shows the mounting of the switch from the top. I have Aqueon Versatop covers on the tank. I didn’t like the hokey plastic strip in the back, though, so I replaced the rear piece of glass on each one with a wider glass piece that eliminated the need for the plastic strip; I drilled and notched a hole in the glass in each for the filter pipes, and drilled a hole for mounting the level switch. Old 35 mm film canisters cover the electrical connections:
This is the initial setup of the tank, to check everything out. I probably won’t put any plants in until the Discus I’m getting grow out a bit. The big take-away from this pic, though, is the complete absence of additional pipes and most contraptions in the tank for the autoWC. The small, tan-colored level sensors in the rear corners are the only extra things.
Here it is with ~40% of the water drained:
Here’s the fill cycle in progress:
With the ¾” line to the laundry room and the full-flow connections, this system is fast
. It only takes ~13 minutes to drain 40% of the water from the 90 gallon tank, and only ~11¼ minutes to refill it.
After all the years of dragging buckets and dealing with siphons on smaller tanks, there’s no way I wanted to do it with a tank this size. Especially with wanting to try Discus, and the high water cleanliness standards they demand. It’s a great feeling to park your butt in a comfy chair in from of the tank with a cold one, and watch the tank do the water changing chore all by itself
, as if by magic. It’s a satisfying feeling.