BBA is a common problem with DIY CO2. BBA is generally caused by low fluctuating levels of CO2. Since DIY CO2 naturally fluctuates, if you can't get the CO2 levels high enough then BBA invariably shows up. The problem with the kits is that they are rated for much lower levels of CO2 than we generally aim for to avoid BBA issues, so they indicate that they can be used on a much larger tank than is true in practice. Further they often sit on the shelves for a long time before being bought, so the Yeast may already be expired before you ever buy it. And finally they often include baking soda to slow down the reaction and extend how long the kit produces CO2, but in a hardwater situation amount needs to be reduced or eliminated to prevent killing the reaction completely. Then of course there are the other issues that can affect production like killing the yeast with hot water or cool house temperatures slowing the production down to almost nothing. It's not unsurprising that most people quickly get frusterated with DIY CO2 and either switch to low tech setups or Pressurized CO2.
There are lots of places to buy CO2 systems. You can buy a custom built regulator from
Rex Griggs, which is especially economical if you want a speciallized setup instead something prepackaged. The Milwaukee Regulators are very popular and avaialble on most sites. The
Aquatic Supply Store was one that was recommended to me early on as having good prices.
When it comes to the CO2 cylindar, you want to buy the largest one that you can hide easily. Make sure the include the height of the regulator in your calculations. Generally it's only a touch more expensive to buy the larger cylindar and just a few dollars more dollars to get it filled since most of the cost of filling is the labor involved and not the gas. I'm running a 5lbs cylindar 24/7 on a 10 gallon, 5.5 gallon, and 2.5 gallon and it lasted six months. With a selanoid and just turning it off at night you could probably at least double the length of time that the CO2 lasts.
As long as you are using liquid hobby grade test kits the only other kit you would probably want is the pH test kit. It allows you to measure your CO2. If you're using a drop checker to monitor CO2 levels, then this is less necessary. There really isn't a hobby grade kit available for either Potassium or Iron, so you need to rely on your plants to tell you when you need more of those. Also since you are probably using hobby grade test kits, you'll want to calibrate them against a reference solution to ensure that the results are reliable and you can compensate for any variance in the test.
Just a quick note that Greg Watson no longer sells dry ferts. He has sold the business to other hobbyists, Alan & Julia Kaufmann, and Greg has moved on to other things in the hobby. The new site is the
Aquatic Plant Food Store. I've also noticed that Rex Griggs has recently started selling Dry Ferts.
Flourish Root Tabs are good for supplementing your substrate especially if you have an old specialty substrate that has been exhausted or are using a nutrient poor substrate like gravel. They can also be used to target feed plants like Swords and Crypts.