8 watt or 15 watt Aqua Ultraviolet UV Sterilizer?

theishkid · Sep 29, 2021

I'm having a little algae outbreak after going for 7 years and I'm looking at starting UV.
My tank is a Cadlights 34 gallon AIO and after rock, sand, equipment, etc. I'm probably somewhere around 20 gallons.

I'm looking at the Aqua Ultraviolet brand since it can hang on to the side of the tank.
Is the 8 watt with a Sicce 1.5 going to be enough for me? It says it's rated for 70 gallons.

The 15 watt says it's rated for 75 gallon but I don't want to go overkill.

Thanks for your help!

C_AWOL · Sep 29, 2021

Only downside I can think of to oversizing is cost, heat generation, and space requiried.

Oversizing one will typically increase dwell time to say the least which should make it significantly more effective at reducing free floating algae/bacteria and the likes or enable you to run higher flow if needed

theishkid · Sep 30, 2021

Does the actual UV light produce a lot more heat from an 8w to a 15w? They would both use the same pump so the actual light would be the big difference.

C_AWOL · Sep 30, 2021

While I can't say what the exact heat quantity will be, the 15w is going to be almost 2x the amount of wattage in comparison to the 8w which in theory should mean almost 2x the energy to produce heat with (I would appreciate if someone were to correct me if I'm wrong).

I do vaguely recall a long time ago that essentially any wattage of a UV is generally close to the same amount from an equivalent aquarium heater if we don't factor dissipation and what not from it being plumbed externally so until someone else chimes in with a better or more up to date comparison, just consider them as that amount of wattage in heating if you want to calculate the difference based on your total water volume + ambient room temperature and with an assumed 24/7 run time.

Ultimately though I would still opt for the larger unit if funds and space allows

Thomas Jedlicka · Sep 30, 2021

sterilizer in my opinion cant hurt to have over sized. should help. also depends what you need in your tank though. is it prevention or solution. either way ive always felt better to go over kill.

theishkid · Sep 30, 2021

Thomas Jedlicka said:
sterilizer in my opinion cant hurt to have over sized. should help. also depends what you need in your tank though. is it prevention or solution. either way ive always felt better to go over kill.

Mostly solution right now. Getting what I believe are diatoms all over the place and on the corals.