OK Just to clear a few things up that I read on other threads
🙂
You were asking about DC's that stay green. This is pretty normal without night time aeration. Mine will be about grass green before the CO2 comes on and be limeade in the photoperiod. Fish and shrimp are OK so all's good.
In the same thread the last post says that you have your powerhead pointing down slightly thinking it would help in the distribution. No-one answered your post there. The poster saying he had his pointing up is using that powerhead only after the lights go off and not for distribution. Like some people will raise their Lily pipes up during lights off to gas some CO2 off.
--------------------------------------
You mention in another thread that your bulbs are '3 years old, Do I really need to change them?'. I'll put my tin hat on and say 'Probably not but without Par testing I couldn't guarantee it. If they were T8 (or T5) on a magnetic ballast then definitely yes however if they are T5 or T5HO on electronic ballasts the research would suggest that contrary to many fishy folk's beliefs there output would have only marginally diminished in 8760 hours (365 days @ 8 hours for 3 years.)
The article I will link to explains that for their example of a 4 tube overhead bay application , over a time frame of 40% of the lamps life (35,000 hours x 40% = 14000 hours) That the
Lumens output will have only diminished in their example from 20,000 to 19,000.
http://lightingcontrolsassociation.org/fluorescent-retrofits-for-highlow-bay-applications/
It was one of the articles I raised on the barrreport years ago in one of my then frequent internet rants. lol. eek 2009. Memories.
http://www.barrreport.com/forum/bar...2-t5ho-does-not-degrade-as-much-as-we-thought
Now we can't take those figures as gospel for your scenario because you will have different tubes to their example, you are using more frequent starts (Their's is based on the fixture being turned on and off once a day for a 12 hour period. And you will have a different ballast as well. They could have a shorter lamp life. I would assume that Arcadia use pretty good ballasts and tubes but have no idea how true that would be.
We can argue about the fact they state of the lamplife of the tubes they have used being 35,000 hours but that figure is by the by. We don't care how long the lamplife is for their calculations because they have judged their measurement on a calculation of 40% which we can say is a test after 14000 hours of use. Doesn't matter if the lamps then burnt out 3 weeks later as we have that measurement @ 14,000 hours.
We can however argue that Lumens are not the measurement we are after but I would say it is safe to assume that if the Lumens had dimished by 5% in that spell that PAR wouldn't be that far off the same amount.
So No you shouldn't have to change the tubes if they are quality and if the unit is quality however no-one can say that for sure without a PAR meter and I will be the only one that will say you don't need to change 3 year old tubes
🙂
However you can if you want to see if it makes any difference. What I would say though is that you should have been able to use 2 on their own even at your depth and have those plants growing fine if the CO2 was right so even if they have degrade massively then having 4 on should have been matching or outperforming 2 new ones.
---------------------------------------------------------------
Another thing is forget the 2ft tall tank measurement. What you need to talk about is the distance from substrate to water surface and also distance from substrate to light.
i.e. My tank is 45cm tall but the water surface is only 37cm above the substrate at it's lowest level. The Light is 53cm above the substrate. Monte Carlo and HM thriving under 1.3WPG Chinese Knock Off LED lighting. That is 6 hours photoperiod @ 1.3WPG with an hour at the start and end with only 0.4WPG. This tank is 144 Litres.
Incidentally that tank is massively underpower in terms of filtering compared to most on here. It only has an Eheim 2224 (700lph) on it with an
Up atomizer (Like you) and external heater hindering the flow.
------------------------------------------------------
Couldn't find a picture of your tank at setup stage or just after. Would help enormously to see it at that point
🙂