This is not likely the case. CO2 dissolved in your water will get pretty much everywhere pretty quickly. I assume you are using an intank diffuser so the individual bubbles might not get everywhere but whether they do much more then the dissolved co2 is a different story and up for some debate. Anyway its recommended that tank filtration be 4 to 8 times turnover per hour. So on a 40 gallon tank that would be 160 to 320 gallons per hour. The aquaclear 110 does 500 gallons per hour. Even with that being cut down a bit due to media etc its still providing a lot of tank turnover. Even if the wavemaker only did 100 gallons per hour (which is unlikely, I would think its probably doing 300+ gallons per hour) its still a lot of turnover that will definitely spread all the water around your tank very evenly.
Most probably causes for slow carpet are 1) its actually normal speed but you think it should be going quicker, 2) inadequate light either because the fixture is not strong enough or because the carpet is being shaded by taller plants, 3) inadequate fertilizer, 4) substrate that is too big and bulky for good carpet growth, 5) your water parameters are such that the carpet plant is struggling more then it would for someone else.
These are just the top most likely things in my experience, it could be something else. With more information we can help you figure it out. Anyway, its not going to improve with a different filter. That said, if you want to ditch the wavemaker and the HOB for aesthetics or some other reason, then a canister filter with lily pipes makes for a nice chance.
Well, I will give a run down of everything with the tank and some pictures too if I can!
*Using platinum aqua soil
*Aqualed aq j 90cm light on 75% wrgb
*Carpet is a mix of montecarlo and Echinodorus tenellus green
*just started using gla dry ferts yesterday but before that was using apt complete 5ml a day
*have a few stems of altenthera renikii and giant hairgrass in corner
* about 3 bbs on co2 with the diffuser going up into the wavemaker.
*has some floating plants cause I'm dealing with a little bit of staghorn atm
Idk what else you need to know but this is a good start I hope. I'm new to this whole co2 thing. Been keeping lowtech aquarium and plants for 5 or 6 years now.
Ph before co2 7.2
Runs 2 hours before lights
At lights on it usually reads about 6.4 to 6.0 the api master test kit chart jumps from 6.4 to 6.0 on test kit