I just replaced the stock pump on my Tunze ATO with this one from the AutoAqua Smart ATO. I had problems with the Tunze losing prime in the top off bin and not being able to recover. Only took a shake to get it to prime, but I came home twice after weekends away to extremely low water in the sump return chamber, so I decided to swap it out. I'm super pleased with the replacement. It is tiny. The suction cups on the bottom grap the bottom of the bucket like you wouldn't believe and, best of all, it is totally SILENT. Way nicer than the Tunze overall.
www.bulkreefsupply.com

Smart ATO Replacement DC Pump
Connects directly to AutoAqua's Smart ATO and Smart ATO Micro! AutoAqua's Smart ATO DC Refill Pump only takes a few minutes to replace, and in all honesty, they are not the highest quality, but they are low in price, making it wallet-friendly to keep a back-up on hand in case your current one...
