It’s not that a lot builds up in between, it’s just that after the last water change I realized there were some significant spots I missed that had a lot of debris built up. Perhaps I’m just overthinking this too much. It’s never going to be 100% debris-free, and my water is currently crystal clear. I suppose that and the fact that the water is testing good as well shouldn’t be any cause for concern.
I'm gonna share the tips that will revolutionise your water changes and gravel cleaning forever!
Number one: Yep, don't be trying to have the tank spotlessly clean and immaculate at all times! It's an easy trap to fall into especially with a first tank, but don't be afraid of a bit of mulm, algae and smaller critters like snails and the teeny bugs that help break down the waste. They turn the poop into mulm, which is mostly harmless fertiliser for live plants, so long as it isn't too much of a build up.
Remember that we're cultivating a mini ecosystem here, not just a pretty tank, and nature is never spotlessly clean! You can do more harm than good in attempting to remove every trace of muck, with every water change and tank clean. With a tank with gravel, I'd aim to clean 50% of the substrate one week, then the other half the next week. Or clean the areas where the substrate meets the glass (an old gift card or aquarium plastic scraper is good for this) so that it looks nice, then suck up the areas with the most mess, like the feeding area, and a light clean in other areas, giving those areas a deeper clean the next time, you know?
But! The trick I'm gonna teach you so that you can clean as much as you want, without emptying the tank of water before you're satisfied!
The trick, if you're using a typical gravel vac syphon into a bucket, just a tube with a sorta bell shaped bit that you stick into the gravel, is to get the syphon going so it's sucking water at a good rate, then stick your thumb over the output end that's in the bucket. This will pause the flow of the water, so you have much, much more control! Then you can move the bell end to the area you want to clean without water pouring into the bucket, place the end where you want, then remove your thumb to allow the syphon to continue and so you can clean that spot. Then put your thumb back over the end to pause it again when you're done, and can continue like that. Moving the syphon around, but only allowing it to flow when you want and when you're ready.
It doesn't mean doing it without removing water- but you need to change a percentage of the water anyway (I do 50-60% weekly) but if you're doing the gravel vac on water change day anyway, this gives you much more time to clean and keep it within your control, while removing much less water, less rapidly!
There's also nothing stopping you from doing a quick sweep with the gravel vac on a day other than a water change day, like if you've overfed something and want to clean up the excess, without removing a huge amount of water you then need to replace.
Useful video for learning more tips and tricks for both starting a syphon without having to suck on the end, or thrash it up and don in the tank - and for pausing the flow. Although in the video, Cory pauses the flow by crimping the tube, which also works - I just prefer to stick my thumb over the end which achieves the same thing, without leaving a crimp in my gravel vac.
But sometimes it's easier to learn by seeing it in action. It was for me, anyway.
Hope this helps!