My new Auto Top-off System The DATO

You would have to replace the aqualifter pump with something capable of the taller head pressure... The AL is only rated for 13" of head, restricting a smaller powerhead might do the trick.... something like a maxi-jet 600 would likely handle 4' head especially if you choke it down to 1/4" tubing, that would slow down the velocity.

That should work just fine for dosing kalk as long as you can reasonably seal the kalk reservoir for elimination of as much atmospheric co2 as possible... TERRIFIC DESIGN!!!

Dave: Thanks! So, will a MJ work if not submersed? IE: Could I attach a feeder line to it?

Repto: You may not be talkin to me, but I don't plan on using it to dose with. Just as an ATO.

If you are going to use a MJ, why not submerse it? If not submersed, you will find you have continually prime it, and the input/output portion does not seal to the impeller body perfectly, so it will leak. Sealing it is an option I guess, but if you seal it properly with something like weld-on you'll never be able to take it apart again to clean it or anything. (silicone has a harder time bonding to PVC/plastic)

MJ's are built pretty solidly, the only way I've had one fail was running it out of the water for a month or so, it was pumping water (recirculating for a skimmer), but it was not covered with water and had no place to dissapate heat, air is a lousy conductor this way. Eventually it just burned up and quit.

The simplistic design was my goal in the whole project.... it works as well or better than I had originally anticipated.

cool. My thought in using it extenally was just that the resivoir container I had planned to use an have already bought is a 5gal water cooler tank (the big, blue bottles)...

My other thought is to do a pressure-fed ATO... This consists pretty much of an air-pump that will handle backpressure, the resivoir, and a float switch setup.

Basically the switch turns on the airpump which pumps air into the sealed resivoir via an airline that doesn't touch the water level. You have another line that goes from the bottom of the resivoir to your tank. So when the pressure in the resivoir builds, it pushes water up into the display, "flipping" the float switch, turning off the pump, stopping water flow.

The pressure setup could work well... the first caveat the comes to mind is the possibility of a siphon forming.

Nothing wrong with float switches, just do yourself a favor and use two in series, so they both have to be closed before turning on the relay to your pump... All it takes is for one lil' baby snail or something to get in the float switch and you'll have wet carpet, which we all know can lead to ISS.
(Irritated Spouse Syndrome)

what about using a water crock despener with a float it would use
0 watts and to refill all you would have to do is change the 5 gal bottle this is what im doing for evaporation..the only thing i dont know is ...

where do i put the floatin the sump ?

and could you use window screan (plastic or nilon) as a block around the float swictch to prevent......ISS. lol lol

ps.... did you happen to read the pm. i sent you yet just curiouse(sp) im fishing for help..

"The pressure setup could work well... the first caveat the comes to mind is the possibility of a siphon forming."

Well, if I were to assure that the water line does not touch the display water column, would there still be a risk of a siphon?... I guess its still possible that it would syphon from the resivoir to the display, eh?

Okay I have a question. This may be one of those questions that has been answered but I need something like this. I like your design. The return line to keep the water moving is great. Now here's the question.

Do you fill the top off with fresh water or salt water?

I've noticed that as the water evaporates, if I add about a gallon of fresh water my SG stays the same. If I add salt water it raises my SG. So what's the deal. The reason I need this is I'm adding about a gallon of water a Day. Yeah Day.

the water evaporates, the salt does not. So, basically, you adding ro/di "fresh" water, you keep your sg the same. Do not top off w/ SW. Your SG will jump through the roof if you top off w/ SW.