Sprinkle, Like any other plant, vallisneria is only mbuna proof if it's plastic, IME. I've kept 70 or 80 species of mbuna, maybe more, over the last 37 years. I've always had good stands of val in other tanks that I could harvest and try in Rift Valley tanks, time and time again. Time and time again it failed. They did eat the val rather than just shredding it like Java fern, though. Plants and mbuna have never worked out for me. Peacocks (sometimes) and some Malawi haps will leave val alone, but it is really hit and miss and by genus or even species. A lot of the Tanganyikan rock and shell dwellers do well with val and other hardy plants such as Java fern and anubias, as do mid column dwellers such as Cyprichromis, Paracyprichromis, Opthalmotilapia and Cyathopharynx. Victorian rock dwelling and bottom-dwelling cichlids from genera such as Neochromis, Astatotilapia, Pundamilia, Xystochromis, Ptyochromis, Paralabidochromis, etc. don't do well with plants IME, but my experiene is limited to a handful of species of each genera and I won't make a total broad statement about these. Some of the predatory Victorians such as Pyxichromis love to hide in stands of val and it helps provide cover for females and subdominant males. This is a good summary of my experiences with Rift Valley cichlids and plants.
Don't forget that there may be plants out there that are tough enough, but that can't handle the hardness and high pH of a Rift Valley cichlid tank.
I will stand by my statement that mbuna and plants cannot be kept together in an aquarium for any length of time without the plants being destroyed. I've never met a plant that a mbuna didn't eat. ?
Anyways, my apologies, Snagrio, I really got off-topic. I just brought up about the acei and plants because you mentioned you really liked the acei. I'll be interested to see where you go with your choices with this tank, Snagrio.
WYite