Algae, Water Quality & Ferts

I have always had algae in my tanks. Sometimes more than others, and at times I have allowed things to get completely out of hand. Obviously I have never gotten a good handle on the relationship of plants, light, nutrients and fertilizers.

The bottom line is that I need to find a way to get the plants growing so well and utilizing the available nutrients that algae is starved out of the picture. I have phosphate in my tap water, and for a while I was wanting to blame that for algae, since that is a popular theme on the internet, but what I need to determine is why are the plants not using up available phosphate? I don't generally have much excess nitrate, and have had to dose that from time to time, so I know excess nitrate is not the culprit, either. If I increase the lighting, then I will often forget to dose ferts, and algae reins supreme. I want it all - great lighting for the plants, but I don't want to have to fuss with dosing ferts and in general testing and calculating additives every day. I don't have time for that.

I have posted pictures of a high light set up (4.75 wpg) on my 55-gal, and that was great fun but I wound up cutting back the light dramatically because it was so much work to maintain this setup.

On the 150 I am running a Coralife 4x65-watt CF fixture, but I wonder if the depth of the water makes this a bit less light than one might think. Currently, even the lower light plants are not growing, and I need to figure this out. I put Seachem plant tabs in the substrate around the crypts and the swords, but so far no noticeable results after at least a week. The plants are not dying, but they are not growing. Phosphate in the water column is off the chart and the #2 reagent turns the sample water black immediately, without having to wait the usual 5 minutes. Are new tanks prone to phosphate spikes? I have not done anything different than I did with the tank where most everything came from - i.e. not overfeeding, not dosing anything but Flourish Excel on an intermittent basis.

I have added a dose of regular Flourish and will see if that helps. I need to be careful and not make too many changes, since I won't know what was the cause of any improvements/deterioration in the plants. I need to sit on things and decide if the Flourish helped, and if so how much and in what way, and determine if anything else needs to be done. I'd like to avoid setting up the pressurized CO2 system I have, since I am trying to keep things relatively simple, but I might go ahead and do that if it means a dramatic improvement in plant growth.