hydor flos work great for me, I had 3, one of them stopped I called the company and told them of my problem they sent me a free new one and a bag full of the internal parts so anytime mine stop working and won't kick back on after a cleaning I just replace the internal workings and they work great, have to replace the internals about once every 4 months ish. Also not sure what sized tank you are talking about but oceansmotions has a cool new revolutions thing for returns, check it out on their website.