You can't mix chemicals willy nilly unfortunately. Just like mixing two different types of automotive coolant fluid can react and cause severe gunking of a cars cooling system.
Don't bother with more mystery chemical flushing systems. Just do it right, dismantle the loop and blocks for a thorough hand cleaning. flush out the rads and start again.
I have used both Liquid Utopia for many years with great success and more recently the EK clear coolant with no problems but when changing from one coolant to another you should always flush the system thoroughly or even better dismantle and manually clean everything.