switching nutes during flowering help!

since veg i have been using 20-20-20 all purpose nutes by plant-prod and i was going to use it for both veg and flowering because i couldnt find any flowering nutes. But today I found some at the local canadian tire. It's plant prod 15-30-15 Flowering Plant Fert. How should i go about switching the plant to these nutrients now? I am 15 days into flowering and have been using the 20-20-20 since. Should I start qrtr strength of this for a week and then full strength it next week?

ALSO

the directions on the label are a little different than the last. This one says MIXING RATES: Mix 3.5 mL of Fert. per 1L of water (1 tablespoon/ gallon)
Then right under it says
FOR FLOWERING HOUSEPLANTS: Mix 6mL of fertilizer per 5L of water.

Those are 2 completely different scales. I'm not sure which one i should follow for my indoor grow under cfls.

On the 20-20-20 nutes it doesnt say Mixing Rates 3.5mL per 1L of water it only says 6mL of fert per 5L of water.

Thanks for the help

If your plants are nice in green and growing well just give them a break on the nutes for a week or 2. Then hit them with the new nutes. 1/4 or 1/2 the recommended amount.

but which is the recommended amount?

3.5 ml for 1L of water or 6mL per 5 litres of water?

confuzzled.

I mix the veg nutes with the flower nutes @ 1/2 strenght (1/4 tsp of each)when I go to 12/12 then go with the flower stuff from their.

that sounds like a good idea. Will do that.