Fish tank woes.....

UPDATE 6/24/2014 - see update below

I am the non-ADD spouse. Our family has had pets over the years and I am always the main caretaker. A few years ago my husband decided that our family needed a fish tank. He spent a couple thousand dollars on all of the supplies and fish. I was not happy about the purchase for several reasons 1) expense and 2) maintenance - who is going to take care of it - I refused  to do anything for the fish.  My husband assured me that he would take care of the tank which he did for about 3 months.

For the past three years, the fish tank goes uncleaned for 8 or 9 months and most of the fish die off.  Our young daughter eventually asks for new fish and then the two of them will make a trip to the pet store to buy more supplies and fish. He cleans up the tank - only to have the cycle start over again.

A few weeks ago the filter died so now the tank is not just dirty, but everything is covered in green mold and it looks disgusting. I don't see any signs of life in the tank.

I need help with the best way to communicate to my husband that I would like him to drain the tank. It pains me to look at it any longer and unfortunately, it is in our family room where we spend a lot of time.

Please help me with how I can communicate this need without causing a fight between my husband and me.   Thank you!!!

UPDATE 6/24/2014

Since my original post, the fish tank has had a complete revamp with a new filter, rocks and fish back. For a few days after that, my husband was obsessing over ph levels, cleaning the sides etc. Then, he loses interest and the fish get nothing except for food (our daughter's job).  Now fast-forward 6 months to the present. I noticed the tank was getting green again and losing water. The fish seemed to be lifeless. So, one night I casually said to my husband, "Hey, the fish tank seems to be dirty. Do you think you could clean it soon? If not, maybe I will see if I can find a company to do it for us?" He said yes and did a quick cleaning of the sides and added more water. He asked what I thought of it and I praised him for his efforts - although probably not enough. I have a hard time giving him words of affirmation (something I need to work on).  Anyways, I mentioned how the mold was still on the bottom and the rocks needed to be vacuumed. Anyways, another week went by and I reminded him again of it. He took care of it, but it always comes with a price. He just can't clean it and be done with it. He had to go out and spend $75 on more supplies and fish. I get it that he needs a reward at the end of it so he likes to get more fish. I just wonder if maybe it would be easier and cheaper to higher someone else to do it for us.  Thoughts?