Re: Two worlds - tarantula
OK then.
I had success running low lighted tanks with sediments under the gravel and low dosing but every time I tried high lighting I failed for the simple reason that I haven't had enough flow so the nastiness the plants are releasing during photo period are driven away from them into the filter where they are processed by bacteria.
How do I measure flow to know it's right, well I don't try to follow the 10x rule but to look at the drop checker.
I place it in the area with the lowest flow away from the CO2 diffuser. If it's blue before the CO2 starts and lime green when lights are on that means the water is distributed all around the tank and gas exchange is done correctly. Ideally will be to have it blue before lights are off.
Why it's not OK to have it yellow all day, I'm not a biologist but I'm guessing that if the PH & O2 stay low all day the bacterial activity is slowed down and you are getting an
unprocessed organic matter build up that is further used by algae to develop (you can notice it very easy, surface scum, slimy glass etc.).
It's easy to improve the flow, just add one or a couple of powerful wave makers and make sure the water follows a circular movement around the tank. Also don't be afraid of having surface movement, the higher it is the better the gas exchange, just increase the CO2 addition or buy a better reactor if the surface movement drives the CO2 out too fast. Filling the CO2 bottle is rather cheap, having trouble with algae on the other hand is not.
My current hardware set-up
You'll notice I don't talk about dosing, it doesn't matter, there are lots of good approaches, PPS & ADA style (more or less the same), EI, mine (I dose everything daily) etc. The only thing you must avoid is to have the tank deprived of nutrients, a tank deprived of nutrients won't have algae blooms if the flow is optimal and you have enough biological filtration (if not ... BEWARE) but the plants will have stunned growth and will decay over time depending on the species and their needs.
Do the light level have any importance, actually it does, every time you add more you need more flow and CO2, more flow because the organic matter released is directly proportional with the light added.
In the end for this 70l tank I'm running a 2000l/h wave maker and a 700l/h external filter. This gives me a 38x flow and I kinda need to increase it because I don't have enough gas exchange but I'm going to keep it like this for awhile until I'll replace the filter with an Eheim wet&dry.
A nice article to summarize the importance of having high gas exchange in your tank:
http://www.lumcon.edu/education/Resourc ... Matter.htm
Hope I've been more or less clear.
Comments are welcome, if any.
Mike
P.S. Gotta thank UKAPS for reaching this conclusion.