Heater wattage question

[SCFatz]

Ive got the new 50g hex cycled well and I thought all was good.Then I noticed my rainbow shark "flashing" on the substrate.Closer inspection of all the fish revealed ich on one of the kissing fish (i'm guessing in the gills of the shark as well).

I have a 200w submersable in there now and its not going to get me past 81 degrees F it seems.Ironically I bought this heater to beat ich in my 29g because my other heater wouldn't get me to 88 in it.

I need wattage suggestions that will get me there in the 50g.Obviously getting to 86 and stalling again would be disasterous.

What do you guys think?

Edit...my next tank will be a quarintine tank.I'm sure of that.

[rich311k]

A 250 watt heater should do the trick, or get another 200 watt and have some duplication.

[sir_dudeguy]

multiple heaters helps too...makes it easier on both of them