Suggestions For Substrate Switching

Hello everyone,
I had set up a planted 40 gal tank about 4 months back with Caribsea Ecocomplete. Its cycled (ammonia, nitrite 0, nitrates 10 ppm) and is fully stocked (102% AqAdvisor). While the fishes have been fine from the beginning, for the last 2 months, all my plants have gradually stunted and were showing extremely poor growth. I have regularly dosed ferts (NilocG ThriveC, 2x dose per week), liquid carbon (glut), have medium lighting (Beamswork DA FSPEC 36"), do not have much of an algae problem and change about 30% water weekly. My plants include easier to grow species like water wisteria, Bacopa monneri, dwarf sag, rotala indica, etc which I have successfully grown before in my previous 29g tank on Seachem fluorite/regular gravel mix.

So I got frustrated last week and decided to check what was going on. The pH in my tank is freaking 8.6 (tap water 24 h resting pH is 7.6), GH is 6, kH is 3. I googled around a bit and saw many complaints about EcoComplete raising pH which seems to be batch dependent. So after researching a bit, I have decided to move on to UNS controsoil which apparently lowers these parameters and releases much lower ammonia than something like ADA amazonia.

So here is my question:

1) Would adding a 1" layer of UNS ControSoil on top of EcoComplete would bring the effective pH down? Of course, I will cycle the soil separately before adding to the tank.

2) OR should I completely replace the EcoComplete with some generic inert gravel from Petco and then top it off with 1" Controsoil (which is quite expensive).

Thank you.

 

I also have been using EcoComplete for over a year now and have a good amount of plants. I was only using Niloc Thrive+ and excel. Within the last 1-1/2 - 2 months some of my plants started to melt, dye, and just look terrible. I started about 2 weeks ago using, Flourish, Potassum and Iron, and I see a big difference in the plants. For some crazy reason my ph is 6-6.5. Out of my tap ( sitting 24hrs ) is 7.5
I add PH up every 2 days and I am keeping it now at 7.5

 

@Dennis57 Your ecocomplete seems to be fine, unlike mine... I have a friend who uses ecocomplete in a low-tech planted tank and his setup has been fine for more than a year now. I think I just got a bad batch of ecocomplete. If your picture is showing the tank you have right now, then I am guessing your lowered pH might be due to humic acids from the rotting plant matter as you have a good plant density (and/or tannins from your driftwood).

 

Yes it is, I do not have any driftwood in the tank. I did remove 2 bamboo plants. about a week ago.
I bought at a LFS but everyone on here said they were not for a tank.