Plans for slow gravity drip top-off

[titanfan]

I searched through here and didnt see any plans for a simple slow drip gravity ran top off system. Maybe if I missed it someone can show me or just let me know how they did theirs. My tank is only 40 gallons but I do see it loses alot to evaporation. I hate adding so much RO water at one time. Im looking for simple plans for an auto top off. Nothing I could depend on for being away as I would not run it while out of town. Justs omething to slowly add the RO as to keep tank temps and readings constant.
Thanks

[Doug1]

Due to changing temps and humidy conditions, few rely on a simple drip top off, to hard to keep the drip rate close in changing conditions. Kent Marine makes a drip bag, like an IV bag that might work depending on how much you lose. If you dont have a sump it might be your best bet. A less ugly but far more expensive alternative would be a peristaltic pump/micro controller setup, but even medical surplus unit is spendy
A float switch could run a power head in an RO reservoir hidden away, might be best option for long term top off depending on the size RO container you can deal with

[Psymon]

What I've done in the past...

Get a 2-3 Gal. glass Jug from a home brewing website, a rubber bung... lol.. bung, a VERY fine tubing, and a standard size tubing. Fill your glass, put it above your sump, Drill your Rubber bung/Stopper with 2 holes, to fit your two tubes, and feed them into your stopper, use some "Plumbers Goop" around the Pentrations. this makes them air tight. The Bigger of the two tubes should go down 97% of the way to the bottom of the glass jug, the other just bearly into the jug.. The smaller light will be your air inlet.





So now take your air inlet, and feed it down to where your fill line will be and secure it.. Siphon the water into the sump bu sucking on the water feed line till it starts to flow, when the water gets high enough to cover the air inlet line the water will stop..

This is a cheap ass way to do it..

Could spend 20 bucks on a float valve, and do it that way.