DB, I dont know if there will be a discount on the RK. I think they have the same deal as Ecotech when it comes to pricing..... very controlled....I bought my 3 Rk's from Premium Aquatics for ($113 I believe) and have added on to them since. You will save $7 but will lose it in shipping. Thank you for planting the seed on the group buy, 2nd time I tried to get one going and as usual EPIC fail............I even begged for someone to start one WTF