Simple automatic top-off system

[huricaneredbone]

So i occasionally need to take off for a week or so and my roommate is about as reliable as hurricane projected-path forecasts. I know my tank can handle itself for a week if i do a water change before i leave and have the roommate feed the fishies every other day (just incase he overfeeds). So heres what i came up with, and it worked great.

I have a 20 gallon long sump, but the compartment where water change occurs is only 2 or 3 gallons when topped off, so this method is a simple way to extend the size of that compartment temporarily. Mnd you, its not pretty, but it works.

Simply get a large tupperware of approximately the same height as the sump, some air tubing, and an air check valve. Fill the tupperware with DI water to the height of the pump compartment when its full. Start a siphon in the airtube into the pump compartment. Now whenever water evaporates from the saltwater system, it will siphon water from the tupperware, thus making it take way longer to lower the water level significantly.

Total cost= 10 bucks or so... Happy vacationing!

[rrasco]

That's not very suitable for long-term use IMO. Here is why. A siphon works by equalizing pressure in all compartments, in essence, it will make the water levels the same. For this to work, the water level would have to remain consistent in the ATO reservoir. If the reservoirs water level is higher than the sump, it will add water until they are equal. If the reservoir is lower than the sump level, it will remove water from the sump adding it to the ATO reservoir.

I would recommend getting a small powerhead (I use a rio600) and a dual float switch. Set the switches to your desired water level in the sump (2nd is placed higher for redundancy), plug the pump into the relay and throw it in your ATO reservoir. It's a little more than $10, but it's safe and effective.

[reyrd]

This method will reduce your salt concentration in your system. Here is why. Salt will travel from higher solute concentration (pump compartment) to lower solute concentration (tupperware) through airtube untill both reach an equal concentration. This process is called osmosis.

[huricaneredbone]

Yea i know, i think i made it clear its just a temporary fix for going on a short vacation. Like i said, think of it as an extension of your pump compartment in your sump. That way you can make it so that a 1 inch drop takes many more gallons of evaporation, and thus more time.

Im not saying this is a cheap and easy way to ignore top off duties, its just a quick, simple, and cheap fix to allow you to take a week long vacation.

[scrombussquared]

This method will reduce your salt concentration in your system. Here is why. Salt will travel from higher solute concentration (pump compartment) to lower solute concentration (tupperware) through airtube untill both reach an equal concentration. This process is called osmosis.
This is true, to a point. Yes, osmosis can and will occur through the airline tubing, but it would take months and months for the salt content to equalize. As the water level in the sump lowers, it will draw fresh(er) water from the holding container, flushing the airline tubing. Then the osmotic process will have to start over again. However, the OP stated he put a check valve inline, so osmosis stops at the check valve. In his application- using this ATO as a temporary setup to keep his system roomate safe- osmosis is not an issue.

[reyrd]

I hope that I am wrong, and make sure you check your salinity just in case. Happy reefing.

[huricaneredbone]

This method will reduce your salt concentration in your system. Here is why. Salt will travel from higher solute concentration (pump compartment) to lower solute concentration (tupperware) through airtube untill both reach an equal concentration. This process is called osmosis.
This is true, to a point. Yes, osmosis can and will occur through the airline tubing, but it would take months and months for the salt content to equalize. As the water level in the sump lowers, it will draw fresh(er) water from the holding container, flushing the airline tubing. Then the osmotic process will have to start over again. However, the OP stated he put a check valve inline, so osmosis stops at the check valve. In his application- using this ATO as a temporary setup to keep his system roomate safe- osmosis is not an issue.

your right, for the most part. It's actually not osmosis; osmosis occurs across a semi permeable membrane. Since there is no membrane its actually just called diffusion. But that is exactly why I used the check valve.

This isn't some magical design, but I figured I would share my simple fix to a common problem.

Reyrd: Thanks for the concern, just for the fiy, I did a thorough water testing when I came home and none of the parameters (except calcium and KH) had change, including salinity.

[rrasco]

I didn't notice you mentioned a check valve, which will help with the issues I described. If you wanted to look at this as a more long-term solution, you could switch it to a gravity controlled system. Raise the ATO res higher than the return chamber and connect a float valve to the end of it. Water level drops, float valve drops, water from ATO is introduced.

As a general rule, I don't trust siphons. I speak from experience.

[huricaneredbone]

I have thought about doing that... The problem is finding a place to put (out of sight) the big tub of DI. I thought about hooking up a DI unit to a tap and hooking up with a float valve but i had a bad experience where tap water got so nasty that even after passing throu my DI unit the ammonia was 7 times higher than the fort myers city water allowance (thats where i lived). I lost thusands of dollars of live stock.

But with the Tub idea i can simply fill the tub and test the water to make sure its ok, and then im set for a few weeks.

[rrasco]

Yeah, I understand. I was initially going to hook my RODI directly to an ATO res and have that refill as well, but didn't for two reasons.

1) RODI work better for larger volumes of water instead of turning on for small periods (membrane lasts longer and TDS creep).

2) I figured the perfect storm would occur in my house and all the redundancy would fail at some point, leaving my ATO on to my tank and a continual source of water. I would be doomed and my wife would divorce me. And I'm not even married.

I have the added benefit of a reef room directly behind my DT, so I plumbed everything through the wall. Tada, out of sight.

If you are interested, here is more detail on that system: http://reefcentral.com/forums/showpost.php?p=20442540&postcount=63

[huricaneredbone]

Yea well i would imagine there is probably a little more space in south texas, unfortunately here in miami i need to be happy with my tiny appartment. Cant wait to finish my phd and get my own house so i can cut dedicate a room to filters and cut holes in all my walls... When i have my way my entire house may be an interconnected reef