Quick Update...
Been very busy lately at work on away at weekends, been difficult to work on the tank. Growth is good, think I am finally getting the CO2 back into shape after the last month of trials with the poor flow etc.
Over the weekend, I was away. Before I went I adjusted the electronic plug timers to slightly shorten the photoperiod. I am using the ones with LCD screens and setup buttons etc.
However, I made a mistake: I adjusted programme one time on, all good. I adjusted programme one time off, all good. I then accidentally ended up setting programme 2 time on to midnight. There's no way obvious to delete this setting once its done. I didnt notice. And worse, I didnt set programme 2 time off to 12:01. So I then went away over the weekend.....
Came back late last night, and noticed one set of lights come back on at midnight, and not turn off....... so then I sawy what I had done: my lights come on at 1430, off at 1730. The second set of lights come on at 1730, then off at 2130. Then the first set of lights came back on at 2400, AND THEN STAYED ON UNTIL 1730 the next day!!!!
Oops.
So in case you're wondering, yes, running like this for two days (and note the CO2 still only comes on at 1300 off at 2100) does cause algae. A lot of algae. Mainly black hair algae, and some fuzzy black beard algae. plus a whole lot of green spot algae on the glass. Plants doing ok, apart from the ones now affected by algae.
So, big water change, scrub the glass. will get round to physical removal of the BBA and hair algae. Have obviously changed the photo period and will actually have a much shorter one today until I can clear out the physically removable algae tonight. And chop down the enormous stems which grew 6 inches over the weekend.
Fish are alright, though another danio committed hari kari last night by jumping out of the tank. My water level is within a centimetre of the top, and though I have cover glasses, there are 3 inch gaps on each side. think I will leave at least an inch at the top going forward.