non-CO2 tank: Vacation Surpise


Lifetime Charter Member
Lifetime Member
Mar 3, 2007
I thought I would convey my accidental 'discovery' of some points Tom and Vaughn in recent posts have been making about algae and non-CO2 tanks.

20gal, non-CO2 + Excel. ADA AS substrate, 36W AH supply, photoperiod = 11hrs
Normally dose at about 60% EI, 2x per week (2x per week I add: nitrate = 3ppm, phosphate = 0.6ppm, K+ = 6ppm)
WC 50% weekly

Just returned from 10-day vacation. Before I left algae had been taking strong foothold. Tank looked pretty crappy. Day before I left did 70% WC and dosed NPK + Excel. Cut photperiod back to 6hrs per day. No ferts, no excel, no WC for 10-day period. Fish were fed by helper 3x.

Low and behold, upon return yesterday the tank is nearly algae-free. It looks far better after 10 days no fert and no water change with lower light.
(Lamotte test nitrate = 2.2 ppm upon return, didnt' bother to test phosphate)

My fert regimen was likely too much for this tank; I had too much light; large usual WCs may have caused CO2 levels to fluctuate encouraging algae.

Less work = nicer tank? Trick will be to see if I can maintain that balance now that I've returned and up-ed the photoperiod.

Tom Barr

Staff member
Jan 23, 2005
Less light can save most folks from algae hell.

The problem is that many hobbyists have been duped into using high light and high maintenance simply because they use CO2.

Low light + CO2 makes for a managable tank over time.
ADA suggest fairly low light and perhaps 3 hours of high light etc on sometanks, but over all, low light + CO2.

Tom Barr

Professor Myers

Guru Class Expert
Aug 24, 2006
Aye, This is a common misconception, and may very well be responsible for better than half the post on algae and maintenance problems. Popular marketing of lighting doesn't help at all, and both the industry, and hobbiest often confuse SW Reef Lighting requirements with those for Planted Aquaria. Then again they have to sell those lights to somebody now don't they ?

Then there is another group of people who glean cutting edge methods off the internet and assume that it applies to all aquatic gardeners. Pushing the envelope comes with a price that most hobbiest are hard pressed to manage.

It has never been a question of whether they are capable of managing the requirements, but ultimately whether they truely desire to commit the effort, or simply sit back and enjoy the "Hobby" Lots of folks make this out to be much harder than it really is.

I might be one of them ? :eek: Prof M