lol, this is all SOOoooooooOoOOoOoOOOOoooo subjective
I have great results with my neo stuff. No light is getting down there because 1) they are filled with clones and the leaves block the light and 2) the cloner doesn't get direct lighting. I keep mine under my flood n drain table, and allow the clones to get residual light.
Everything is so so subjective, and honestly, as long as you follow some of the suggested steps in here, you'll be fine.
Take this for example. I tried a clone dome, and lost 20 of them within 2 days. Loads of various issues caused it, but I won't get into them right now. So I cut another 10 days later, and by the next day they looked like they were going to die. I put 3 of the best looking ones (just 1 day after cutting and having them massively wither away to a wet noodle consistency) and put those 3 into separate "double shot" shot glasses, 3/4 full of water. I left them under my flood and drain table, just to see how they would fair. These were CLEAR shot glasses, and light was going right through them. Within 10 days, I had roots and 2 weeks I was able to transplant ALL 3 into Sunshine Advanced Mix #4 (soilless)
So sure, algae can build, light can not help root development, you may not have enough air, you may have too much, it may be too cold, too hot... your right arm may hurt one day, and left toe the next, blah blah blah lol...
Point is, I never changed that water, it was clear through and I got 3/3 to TAKE and throw roots after having them wizzle down to spaghetti texture.
I'm sure, whatever you do with all this info laid before you, that you'll start to figure this whole thing out and come into your own. Don't let 3 of us, giving you 3 various thoughts (generally consistent but quite varied) make you panic! There's nothing to panic about. Shoot, the stuff is SUPER expensive. Go on out and get stuff to make two types of cloners... and heck, you can always take plenty of clones, so there's no fuss.
Green mojo for everything you do :aok:
Here's some pics of said shotglass clones:
http://www.marijuanapassion.com/forum/attachment.php?attachmentid=204167&d=1368062435
http://www.marijuanapassion.com/forum/attachment.php?attachmentid=204413&d=1368666636 (oh hey, it was 4 of them, not 3)
http://www.marijuanapassion.com/forum/attachment.php?attachmentid=204632&d=1369191572