personally I wouldn't mess with the recomended ingredients for a cleanse.

Yes, in fact I think it is best to get used to the psyllium before adding the bentonite. That way, you will know what the effect is of the psyllium. Just don't consider it as part of your cleanse program, rather a warm up. You can find Bentonite in most health food stores, in the intestinal cleanse / bowel health section. It comes as a thick liquid in a bottle. The psyllium comes as a powder. Don't taste the psyllium dry.(I found this out the hard way.) It will cement itself to your mouth. It absorbs water and becauses gel like very quickly when you add water to it. I usually put a tablespoon in a glass, (consider a large disposable cup or wash immediately afterwards), add water and stir quickly, start drinking, stir, add water, drink, stir, add water, until gone. Once you are familiar with this, and find your bentonite, put it in on top of the powder, and then add the water. I do not like the 1 teaspoon psyllium to 1 tablespoon bentonite, and rather prefer the other way around. Bentonite is clay and can stop you up a bit if you are not careful. I would start with 1 tablespoon psyllium and 1 teaspoon bentonite, and slowly increase the Bentonite as you get used to it, if you so prefer.

I have used psyllium on it's own, sometimes when I run out of bentonite, sometimes when my body absolutely does not want any more bentonite.
I would try with just a teaspoon of psyllium husks per glass of water. See first how that works for you before you increase the dosage.
Psyllium with not enough water can also make you constipated....
If I take one Tbsp of psyllium, I need to use 2 glasses of water. Anyhow, that's how my body works, we are all different and need to experiment...

I'm now using Sonne's Bentonite in a nice liquid form along with their Psyllium - found it at Wild Oats Market. If you have a health food/nutrition place in town, I'm sure they'd have it there also.

For the 1st 3 months of colon cleansing (yep, I started 6-6-03... still goin' strong! At my age, there's lots of garbage to dump!) I used "Colonix" from http://www.drnatura.com/. It combined an anti- parasite cleanse, the fiber and an herb tea to help with the cleansing. Nice program but pricier than Sonne's. Anyway, they both work! Getting out lots of old "stuff"! Ropes, chunks, you name it! Cleansing is awesome!