Hey,
Good start especially if you are just expirementing with planted tanks. Aquascaping takes practise and alot of imagination.
I don't know how you setup your tank or specs of your tank so I"m going to make some assumptions based on what I see.
Assuming you want to get into and do more advanced planted systems I would highly recommend you invest in a canister filter. Sponge filters don't really do the trick when it comes to highly planted aquariums in my eyes, not only do they create surface agitation they are an eye sore. If you don'tk now why surface agitation in a planted tank is not horrible but should be avoided it will come up in my next point. The powerhead I don't think you really don't need - with the sponge filter yes I like to see you have some water movement in your tank. If you upgrade the filter to a canister like an Ehiem I would suggest you can get rid of your - Sponge filter, Powerhead, Heater. All these would most likely and can be included in your filter depending on which model you go with. Also by combining them all frees up some tank space and in my opinion not only gives you more space for plants it is a little easier on the eyes.
Back to the sponge filter - I'm assuming your tank is between 120-180 Gallons? I also didn't see any other filtration(I'm sorry if I missed a canister or something) Once you start adding fish which I hope you do because their waste will also provide nutrients for your plants. That lonely sponge filter won't be enough.
Lights seem to be doing the trick, I'm not sure how many WPG you have but if it works why change it.
Ferts? Not sure if your dosing I would suggest at minimum dose Florish, Look into the PPS-Pro Method.
Props to no Algae on the glass that can be the biggest balance with Photo Period, and Fert doses which conribute to Algae control.
Substrate - I'm not one for the rainbow 6 different coloured Clown vommit. Black White not to bad, I'm a fan of trying to keep everything as natural as possible. I personally use Playsand, I've found that you can grown plants just as well if you know what your doing rather then investing well over 200$ for your tank I would say for Eco-Complete or Florite. Playsand 5.99$ for 25Kg's - 2-4Inch base layer. Playsand doesn't have any nutrient properties in it like the Eco-Complete or Florite but to be honest most plants can get enough nutrients to live from the water column so as long as your dosing ferts and your light is enough you'll be fine. If you see a plant struggling throw in a root tab most of them last for 6 months and are good for a pretty decent area.
Adding plants/Starting over - I strongly suggest adding all the plants you want at one time. Although your wallet will take quite a hit it's worth it in the long run on Algae control and overall just the hassle. Your plants will compete with the Algae hopefully beating it and not allowing it to get out of hand.
Co2 - If again your serious about a planted tank, Pressurized Co2 is a must!! That is if you want Co2 at all. If you have a 2 Litre coke bottle DIY co2 on your currently tank that is definetly not even close to enough. 1 Co2 DIY would be enough for a 20G tank. You do the math
Your co2 is most likely being outgased by your surface agitation that's created by your sponge filter. What are you diffusing your co2 into your aquarium with? Through the power head i'm assuming(but I don't see a co2 line connected)?
Anyways man, I hope this isn't to much and definetly a GREAT START to a planted aquarium. After you get this one going and your happy with it, I guarantee you'll start another. Things come with expirence and you don't learn if you don't make mistakes! If you provide me with your actually numbers in Filtration, Watts and Index on your Lights, Photo period, Fert dosing and Tank size. I would be more then happy to help you iron out some things that seem to be in muddy water.
Good Luck!
