In reply to A. H. …….. I missed that reference in Walstad. I just can’t help but think that if copper or lead were a problem in modern aquariums in houses with copper plumbing than there would be a lot more in the literature than just Walstad.

Walstad fails to provide instances of where heavy metals or other “toxins” have poisoned aquarium fish. The only water supplies that have toxic levels of heavy metals are a few mountain streams that drain mine dumps. It just is a non-existent “problem”.

In reply to Daniel …. I would simply measure the nitrates and only do the water changes necessary to keep the nitrates less than 80. Easy!

First off let me just say how awesome you are. Your knowledge and experience are priceless. I am a firm believer that experience is the best teacher. You actually have experience and an education with research to back up your claims. That combination got my attention. I actually stumbled upon a YouTube video of a guy who proved that seachem matrix didn’t lower nitrates. Man he took a beating in the comments. Sometimes people can be stupid. You are also correct about Kev with Kaveman Aquatics. He actually used to have his fx6 loaded up with pot scrubbers and decided to try biohome instead. Then after seachem hired him he switched to matrix. He claimed matrix lowered his nitrates. He actually did the nitrate test on camera. I admit they were lower and I questioned your claim. But Kev made a mistake. He recently moved to a new home and video taped the move. Behind his 3d background was growing a pothos plant that had been in there a couple weeks longer than the matrix in his filter. It’s the plant reducing the nitrates not the filter. He just kept it hidden all this time. I like Kev but that disappointed me.
Anyway my question is I have a 75 gallon tank with approximately 40 mbuna in it. I have read that your overstocked tanks do water changes every 3 days. I don’t have a drip system because I rent my home. I do have a water pump that I use to drain my tanks El quicko. I currently do 1 water change a week for both my tanks but my mbuna tank I was wondering if I should go back to 2 a week. Both my tanks are HEAVY filtered. My Mbuna tank has a pennplax 1500 elite canister filter, an Aquael Ultramax 1500 canister filter, and 2 seachem tidal 110’s hob. All my canister filters are now set up as you recommend with 1 basket of 20 ppm sponge, 1 basket of 30 ppm sponge, and the rest with the k1 plastic media. The Aquael Ultramax filters hold a crap ton of that k1 stuff. The 2000 on my community tank holds so much that my first order of k1 was about 4 gallons of media and in 3 Aquael baskets it held about 70% of that entire box. I ordered more lol.
So is the once a week water change good enough for my little mbuna monsters or should I go back to 2. I do an 80% water change for them. I will say after the water change they are much more active for the next few days. Oh I forgot. I have 2 wavemakers in my mbuna tank also as you recommended. The more powerful one is pointed up and the other is on the opposite side pointing into the gravel. Hope to hear from you soon!