I'm toying with the idea of buying the above filter for a future aqaurium. However, the spec shows the inbuilt heater is only 210watt. Surley this is only large enough for tanks up to 360 approx?
http/www.eheim.de/...tail_37395_ehen
The difference with heaters that are built into filters is the amount of water contact and flow around them. The water will pass over a larger surface area and also circulate quicker giving a more constant temprature rather than the on/off you get with stand alone heaters.
The issue you have with built in heaters is maintance. They need to be cleaned more regulary as build up off minerals can occure which then reduces the surface area that water is in contact with.
Older filters with internal heaters used to fail due to lack of maintance and often the circut quality but I haven't heard much about the new Eheims having any issues.
The only issues with the filter shown is the price, at £380 (retail, with no media). For around £330 you could get a Eheim Pro III 2080 and an external in-line heater with media.
Or check out the Eheim 2180. I found that for sale for £320 and has a built in 500w heater if you are worried. With media you would be looking at £380. I tried to find the 3E 600T for sale online but it seems most places don't have it stocked and not showing prices. One place had it on for £440 but again not in stock.
Kind Regards,
Adam