Well, isn't that a kick in the pants!
I actually had no idea about the content of the substrate until I posted that link. It appeared to me to be a granitic based sand mixture. It just seems to be another twist in my search for an alternative substrate. I'm glad you pointed it out Steve, although it may mean that I have to remove my substrate
I still have my happy face on but I must say that (in general) the nay saying is a little frustrating and non conducive to exploration. I think some are misconstruing curiosity with a rejection of known principles.
Yes, Ca based substrates have advantages that I am quite aware of and agree with but we don't actually have Ca based substrates off of the west coast so, if we want to develop representative examples of these areas, we have to look to alternative substrates.
Yes, chillers are an easy and effective way to reduce tank temps and they will do the job but are they the only way? Should they be the first line of temp control or can we reduce HP requirements by taking advantage of passive forms of cooling first (like eliminating forms of heat input such as using inline instead of submersible pumps, eliminating power heads by using surge tanks and making use of the stable cooling effect of those great big concrete slabs)?
Yes, temperate flora and fauna need cooler temps than their tropical counterparts but we really don't know what the temp requirements are for some marginal tidal zone species. Right now we are just guessing.
I guess that's the motivation behind my build - to try/learn something new. This field is pretty undeveloped and I'm not afraid of making a mistake or two along the way in order to push the envelope a bit. In the end, if I have to plug in a chiller or anything else, at least I'll have exhausted my alternatives and we'll have something concrete to offer the next time someone tries the same thing.