How Much Water Should I Change?

[Rob5]

I have a 200litre heavily planted tank
 
I use Easy carbo and TNC complete and the plants are doing really well but the algae is starting to build up again after getting rid of it a few weeks ago
 
I have an external Eheim 2073 filter, 1050 litres an hour, internal Eheim pick up 2012, 400litres an hour and a Hydor Koralia 1600 so i know that the flow is good
 
I do a 50% to 60% water change every Friday and two hours before lights on
 
Obviously i have a CO2 fluctuation problem
 
I was reading on the forum on here that maybe i am changing too much water
 
Can any one advise me on this?

 

[SLIM]

Whats your photo period?
And how strong are your lights?

I have pretty much the same set up as you jus on a larger scale. I dose micros macro easycarbo and have a photo period of 8 hours and I have no algae. However I only change about 30% of my water a week. Once a month I make a point of missing a water change too. Remember nitrates are not a bad thing in a planted tank.

Are you dosing your easycarbo before lights on?

 

[SLIM]

Also I assume your dosing easycarbo everyday?

 

[Rob5]

I have 3 x T5 39w lights on for 7 hours a day
 
And dosing Easycarbo daily two hours before lights on
 
Maybe i should cut down to 30% and miss 1 water change a month as you do and see if it cures the problem

 

[SLIM]

Yea well it cant hurt. You seem to be doing everything else right. You do have a lot of light tbh but your photoperiod is not too long which should balance that out. If you still have problems after afew weeks, might be worth taking a bulb out and seeing if that sorts things?
My last tank was a 260L with 2x 39w t5s which was plenty of light.

 

[Rob5]

I can easily flick a switch and turn one of the lights off if need be and might just try that first of all
 
Thanks for your advice SLIM, it is most appreciated

 

[SLIM]

No problem