Wow, I haven't seen this products from Ikea. Will check it on our local store next weekend.

About improvement:

1. It's likely that you got rootroot because of insufficient amount of oxygen in water. According to the structure of this grower, you either used not enought amount of stones, or you have distributed them unevenly. And also, 15min of aeration every 1,5 hours isn't enough for any DWC-like setup. Increase it at least to 15 min every 30 min.
2. Change your pump to the noiseless one - I usually recommend Tetra products, they are reliable and powerful. In general, they justify their price: https://www.amazon.com/Tetra-Whisper-Easy-Aquariums-Non-UL/dp/B0009YF4FI/ref=sr_1_6?ie=UTF8&qid=1529841047&sr=8-6&keywords=silent+aquarium++air+pump
3. About light - it's better to switch to specialized agronomic light. They will be more effective, but will give violet light:

https://www.amazon.com/RAYWAY-11-5inch-Greenhouse-Hydroponics-Vegetable/dp/B06XPGNLCW/ref=sr_1_13?ie=UTF8&qid=1529841312&sr=8-13&keywords=grow+led+strip

https://www.amazon.com/dp/B01IVQ96KY/ref=sspa_dk_detail_2?psc=1&pd_rd_i=B01IVQ96KY&pd_rd_wg=uu64E&pd_rd_r=DT9YC0VHFAN5VCWHNA05&pd_rd_w=nFiJN

I've found the one with yellow-light, but I don't know, is it good for plants (they don't provide adequate spectre info): https://www.amazon.com/Roleadro-Upgrade-Developed-Spectrum-Generation/dp/B01HI3AFYM/ref=pd_sim_86_12?_encoding=UTF8&pd_rd_i=B01HI3AFYM&pd_rd_r=69G0G3YSD1DN5NCPFQZD&pd_rd_w=k0I8Q&pd_rd_wg=RZTJ2&psc=1&refRID=69G0G3YSD1DN5NCPFQZD

Feel free to ask any questions!