Has anybody used the XL with the gravel washer attachment. Back in the day, I had an XL that I absolutely loved. Luckily I am mechanically inclined and was able to use the filter with no hassles. Back then they didnt have a recharge valve or the gravel washing attachment so charging the filter was a chore. I like the idea of the gravel attachment since is such a chore to vaccuum gravel and balance getting the job done without removing too much water before you are done.

The concerns I have are as follows.

1. does it hurt the good bugs in the gravel with too much suction
2. is the gravel attachment quality and will it withstand the chore of deep gravel washing?

My next question is adding an extra filter for strictly biological filtration although mechanical will be present as well. My therory is this. I have a 30 gallon tank with an aquaclear 50 on it. I am certain that this filter is not enough for a goldfish tank. Ammonia and solid waste is our biggest enemy and I was thinking of another aqua clear 50 with nothing but 3 sponges set to a low setting or maybe 2 sponges and bio stars. So in therory, I can take the main AQ50 and clean the sponge as needed and rotate sponges between the first and 2nd to keep biological filtration at its peak. Between the 2nd filter and the mechanical filtration of the xl with the gravel attachment, I should be able to keep waste down to an absloute minimum.

Your thoughts will be greatly appreciated

With out a doubt, diatom filters are the most thorough mechanical filtration there is, but that is also their drawback. Especially if you want to use one to filter the water during gravel vacuuming. I haven't actually used one, but my guess would be the the filter would clog up before you could finish vacuuming the tank. And then you'd still have to siphon water out of the tank to do water changes.

I Googled "Vortex diatom filters" and found their main site. No where do they mention a gravel vacuum attachment for any of their diatom filters or have it listed in any of the parts lists. Where did you find an XL with a gravel vacuum?

Here's the link to Vortex Innerspace Products, Inc.

http://www.diatomfilter.com/diatom_filters.htm

Your plan for using two Aquaclear 200/50's on a 30 gallon tank sounds pretty good to me.

here is a link to the picture of the gravel washer.
http://us.st11.yimg.com/store1.yimg.com/I/...6_1885_31601436

You're correct, I dug around the Vortex site a little more and found it.

http://www.diatomfilter.com/products/grave...r_model_gw1.htm

Go for it... It sure can't hurt anything.