Automatic waterchange with top off design - please gimme some feedback
 

So i woke up in the middle of the night (4:37am) with this brilliant design for a automatic water change system

Here is the model of it:
http://dl.dropbox.com/u/2361330/Aqua...0build/AQ5.png

So here is basically what happens
All this is wired into the Apex controller and break out box
A pump sits in the left side of the sump by the skimmer and just waits for XXX time. When the time comes (lets say Sunday 4pm) Apex controller turns off the skimmer and return pump and solenoids. This levels the water out in the sump. The pump on the far right of the sump starts pumping out water from the skimmer area down a drain. Once it hits the lower float valve it stops the pump. Next the pump in the SW mix container turns on and starts pumping water into where the drain pump was pumping out of until it hits the upper float valve. BOOM, water change

After this is done, return pump is on, skimmer is on
solenoids turn back on and the sw mix solenoid starts pumping water into the sw mix container until it hits the float switch. i come home from drinking around 8pm, pour in XXX amount of salt into the sw mix container and wait until the next water change.

thoughts?

The water changes will only be as big as whatever my skimmer area can hold.

The only thing that I would throw into the mix is that when you turn off the return pump, your sump will fill with some additional water from the display until the back siphon stops. At that time, the water level will most likely be over your walled off skimmer area and you will be doing a much larger water change that you originally planned. As such, you just have to make sure you have enough fresh SW available to handle this amount.

That would be a lot of automation but it seems doable.

wouldnt it only be the amount of water thats in the pipe that is draining from the main display?

my SW mix should be big enough but if its going way over the wall i dont want the pump pulling in any refgium stuff.

It depends. If you nozzles for your return are below water surface they will drain until air is let into the pipe to break the siphon. Unplug your return and see how much of your display drains to give yourself an idea.

This is a similar design that I have in mind for my setup. I also have a similar controller (RKE) which can be programmed like the Apex. What I would do is time how long it takes for all of your syphon to break. Program that time, plus about 1 to 2 minutes into the Apex just before the it starts your pump in the sump. This would prevent you from dumping out too much water from the sump.

Seen a really simple automatic water change system (believe was on RC) that was just dual matched dosing pumps running at the same time, one to pull from a reservior, other from the sump. Pumps were on a timer with on times throughout the day to change about 15 litres.

No high flow pumps, no float switches or water level sensors to mess up. Being matched wouldn't confuse a ATO.

Good idea. Only hassle I think you will face until you get it totally figured out is salinity.

I don't see anything inherently wrong with the design but (and I don't know if the apex can accomodate this) I'd suggest that you have to push a button or something when you add the salt to your mix tank. That would preclude you forgetting to add salt and having a bunch of fresh water added to your tank by mistake.

The ATO wouldn't cycle again until the button had been pressed, confirming the water for the cahnge was in fact, salt water.

auto change
 

the only problem that i really see is the build up of deteris in your display tank-i do a 30-35 gallon change every week in my 220,and i have to do it manually just to get rid of the excess deterus

The only comment I have add to all the other great comments is that I don't really see where you are going to put the plutonium rods.. You seem to have accounted for everything else :surprise:

the reason im not using dosing pump is because of the chance of the "drain" getting plugged since the pipes are so small.

Also I could remove the "drain" pump (and one float) then just use the return pump if I could find a 3/4" electronic solenoid. I would put a T connector where the return goes back up to the tank.

If the apex controller will let me, ill do a "turn on until float switch is active" or "2min is up" this way i cover my butt twice.

I also might put a emergency drain from the SW mix tank to the drain on the other side just in case the solenoid gets stuck open and the SW mix tank overfill. Im just not sure if I can put a bulk head on a plastic container.

As far as the return siphon, I haven't decided yet but I might not have under water, might just be barely above the water so i wouldnt get to much siphon.

If you do this you will get some (or a lot) of splashing and depending on where your light is possibly lots of salt creep on your light (or edges of your tank). Plus you are introducing noise to your system if you do this.

That's how I am planning my Auto WC system. If I ever get time

Did you do a wiring diagram?

there is no real wiring
im using apex controller, everything plugs into a 8port power strip that comes with the controller and the floats plug into the break out box

Have you got your Solenoids yet? I have a shipment coming in soon, if you need some.

nope havent bought them
what kind you got?

I say it looks good. I would set it up to do it every day for two weeks with freshwater only as a trial befor you set everything up in salt though. this way you can time it so it happens while you are there and can do some fine tuning.

Steve

Looks like a good setup. A couple of comments I have... You'll need a circulation pump and a heater in the salt-water make-up tank to mix the RODI water with the salt and heat it to the desired temperature.

If you want to go to the nth degree, you could have another hopper with salt mix with a load cell on the make-up tank. You could automate adding the salt mix, the water and the mixing. Unfortunately, Apex controllers don't take generic 4-20 mA analog signal inputs or outputs. For this sort of thing you'd have to buy a separate PLC (programmable logic controller).

I was thinking of automating this water change. But as others have mentioned, I use water change time to clean the DT of hair algae, cyano and detretius. Except for scraping algae, this is the only thing I don't have automated in my tank (Auto-feeders, ATOF, Ca Reactor, Light timers, etc.. make life easier).

+1

I don't know if anyone has mentioned this, but I'd have a reservoir for the RODI line instead of plumbing it directly into your tank. In the unlikely (just like every other disaster preceeding event that seems to happen just a tad too often in this hobby) event that the solenoid fails, it won't flood your system - it just floods a reservoir that could have a built in overflow system. It would involve one extra pump, but that could be the pump that saves your house from becoming a mess, and saving your tank from a crush inducing salinity swing.