I think ATI is winning so far, looks nice and simple and relatively cheap. 2 part would be good but given I don't want to do water changes I would also need to add trace elements and presumably ICP test regularly to check levels.
The red Sea reef care program looks overly complicated to me. I gather the 3 foundation bottles are just alk, ca and mg so I would also need to buy the 4 trace elements bottles, seems overly complicated and a bit of a rip-off.
So ATI plus Triton style sump for nutrient export is the winner I think.
Thanks for you help
Nick