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How to deal with Over-lighting 2x55w PC on 60L (=5.5 w/g!)


1 Mar 2010
USA / London
Here is a PM exchange between me and Simon D. Hope you find it interesting. If you have anything to add I would be glad to hear it. Cheers.

Hi Simon, I noticed in a post that you had 2x55W Power Compacts over a 60ltr planted tank. I have done the same and I am worried that I have gone overboard...What problems did you encounter (inadequate ferts, algae, heat, etc) and can you recommend strategies for dealing with these?

I guess reduced photoperiod and also staggering the lighting (only 1 on at a time) could help-as they have separate switches.

Oh, I have pressurized CO2, ADA Aquasoil II, and an eheim 2213 canister filter on it as well.

Thanks for your input!


Hi Gerard,

I did encounter problems with the 2x55W PCs. Your looking at over 6WPG :oops:

It was difficult to analyse, initially, because I had changed so many things at the same time and wasn't experienced enough to understand that the over lighting was just an invitation for algae to come do as it pleases.

At the same time I installed an eheim 2217 (1000 lph) as opposed to your 2213 (440 lph?) thinking that flow of that amount (16.66 x p/h) would be excellent in getting ferts and co2 around the tank and to every corner and beleived I wouldn't have a problem.

Because I have a heavily planted aquarium, flow was slightly restricted so I added a koralia 1 (1500 lph) to give 40 x turnover p/h.

CO2 is being pumped in to it's max via FE (without killing any livestock or them suffering) 2 and half hours before lights up and off 1 hour before lights down

I was still suffering some algae problems and not having the facility to turn off one power compact tube, I reduced the lighting by covering the condensation lid with grease proof paper to effectively dim the amount of light. This has worked well and now have a virtually algae free planted tank. This is luck and experiment, not calculated judgement, and I have no way of knowing how much WPG I have getting to the plants but they are thriving.

I originally bought the 2 x 55pc as an investment as I needed new lights and thought I was going to get a 4 footer..... A year or so later I've got the same tank same light.....

Hope this helps.

Simon's second PM:

Sorry Gerard, I didn't answer some of your questions:

1) inadequate ferts - I virtually double dose the EI recommended - but strict 60-75 % water changes weekly (not sure if this is advisable but it works for my set-up)

2) Algae - previous post

3) Heat - yeah they throw out plenty but won't effect the water temp. I've got a hood and had to convert it to accomodate the fittings. This has made all plastic fittings inside the hood very brittle and am now experiencing lots of small brakeages (within the hood) that I need to shore up.

4) Photoperiod - I did reduce this considerably, down to 4 and half hours at one stage, and now only run it for 5 and a half hours, shame really, missing out on lots of veiwing!

As I mentioned plants are thriving and algae free.

Generally speaking, I wouldn't advise high lighting and I've got all the equipment to combat the kick-back.