In a sump filter to suit a 175gal tank whats better 25mm or 40mm balls ?

Next whats the average amount of balls used for the answer to the above ?

last one promise what do you guys heat bigger tanks with ?

thanks in advance

Gaz

you will need around 2L min media I have 5L on my 150g. either large or small will be fine, whats the cheapest? go with that. 300watt plus heater will do great. don't go with much smaller or it will be running all the time and take a long time to reheat if the temp ever drops. I run 2x300w to make the temp even and as a backup. they switch themselves off once the right temp is reached so what may look like over kill isn't so bad.

Thanks for that
Much appreciated
Gaz

If you get plenty of sponge or filter wool before the media it will keep it clean for a long time, and make maintenance easy.