Since beginning my experiment with 'All-in-one' in my 130 x 50 x 50cm 325 ltr tank. http://ukaps.org/forum/viewtopic.php?f=11&t=3157 I have been very happy with the results in terms of plant growth. However the algae issue is baffling. When I started, BGA was a problem. That's diminished quite significantly but the new problem is now BBA! Since adding a powerhead, flow is no longer an issue (probably contributed the the demise of the BGA). I also bought some KH4 solution and B Blue from AE and used that in the Dennerle drop checker which confirms the CO2 is about right for my low light tank (0.75wpg - 2 x 36 watt T8 tubes Trocal Amazon day and Trocal special plant). BTW. The drop checker certainly changed my approach to CO2. The Dennerle PH controller used to switch off the magnetic valve at PH 6.8 but the drop checker revealled at that PH level the CO2 content was too low. Although I am still tweaking, the drop checker is now creeping towards lime green but the magnetic valve is now switching off at PH6.6. Probably the acidity is influenced by the 2 large pieces of bog wood in the tank. Anyway the bottom line is I think the CO2 is fine but the BBA remains a growing (pardon the pun) problem. My next plan of attack is to add some additional light, probably an Arcadia single 54 watt T5 to the existing T8s and increase the All-in-one dose to 40ml per day of the double strength mix. Anyone any thoughts on this?