Good, then you'll like this
You will have to buy some 2" acrylic, but the good news is that its allot less expensive than the 6" On Cris Parris site he uses a python (gravel cleaner) for the smaller bio tower. You will need a small section of 8" (for the collection area) and a section on 2" Unfortunately you cant make the whole skimmer from 6" I can tell you for sure, you will be much more happy with a downdraft. I wanted to mention... At the top of the bio chamber, do you have an air intake? This is essentially just a hole to allow air to get pulled into and down the bio tower. Should be about 5/16 to 3/8" That also makes a substantial performance difference. I just got the skimmer up & running a couple of hours. ago here's a couple pics. which is preferred a wet or dry foam ?
You want the foam dry
Looking at the pic, you have about 7" of water in the main reactor, you really want about 1/2 of that like 3 -4 inches of actual water. As I've said in the commercial brands... they run them with no water in the main reaction chamber.
I'd be surprised if you can get the skimmer *tweeked* using the valve you're using... but.... I suppose its possible
Its looks like you have the valve wide open and you still have 8"in of water in the tube. I believe the more *water* you have in the main chamber the less throughput you have of the skimmer. It looks like the thing is functioning and it is... but just not as effectively as it could be.
Also thats what 1" pvc on the output?? I think you need at least 1.25" but... lets see.
I'd guess it will take the skimmer a few (4-5 days) to kick in I have about 3" in the main chamber, its been running for about 12 hours now, seems like there is a awful long way for the "froth" to travel to get to the collection cup, you say it should kick in a few days? and yes there is a 3/8" hole in each bio tube.
Yes... I know what you mean.. "a long way for froth to travel" that's a common concern. and a very real temptation to run it 1/2 way up of even 3/4 full of water. The problem with that is when it does "kick in" it will overflow badly AND your overall skimmate will be very watery (tea like). Not what you want.
The skimmer will take at least 3-4 days to kick in and when it does, the main chamber will fill with *large* (1.5 - 2") clear to white bubbles these will get smaller as the skimmer adjusts and finally you will get the even flow of large (one inch in size) bubbles constantly churning and rising in the main reactor. The skimmate that does overflow will be the consistency of thick algae or thin mud, much of the maintenance is done by wiping the inside of the upper portion of the chamber to remove the mud like skimmate.
The skimmer will be fully kicked in when you run with 3" of water the entire main reactor chamber is filled with large bubbles it looks like the skimmate is almost shaving cream consistency (not density) but how it seems to "stand up" as it overflows the main chamber
It takes patience
You can run it higher... but eventually you will resign to running as recommended Its much more effective