these are great plants to get in your pond. Just want to let anyone know if you are curious, my pond was very green for weeks. I used a product called algaefix from drfosterandsmith.com and it worked to clear up the algae a little, but didnt quite get it completely clean. I was using that for about 2 and a half weeks using it every third day. Just last week I bought 5 water hyancinths (and one water lettace) from the local grocery store and within three days my pond cleared right up. My pond is about 1000 gallons and it has been in the mid 80s to low 90s during the day. I am always giong to buy these plants from now on because they worked wonders. Also, I do not have a UV light and was really looking at them before buying these plants. It is the easy way out to clear up your pond (and some people say its the only way), but if you need to save money, like myself, use lillies and buy a small amount of water hyacinths. I say buy a small amount because they spread rapidly in warm conditions. also, i do have a few different types of plants but not very many of them.