How often to change res?

Hi ive got a wierd home made setup im using i was just wondering how often the res will need to be changed?
or do i just top it back up with water n nutes?

i have a setup that has a air pump and a water pump that is running to 1 plant that hasnt had its roots grow all the way down to the nutes yet.
the ph levels are still the same for the last 4weeks

Sorry its my first indoor grow

photos dont seem to be working here are direct links

http://img535.imageshack.us/i/0202101236.jpg/
http://img132.imageshack.us/i/0202101235.jpg/

StAlKeR said:

Hi ive got a wierd home made setup im using i was just wondering how often the res will need to be changed?
or do i just top it back up with water n nutes?

i have a setup that has a air pump and a water pump that is running to 1 plant that hasnt had its roots grow all the way down to the nutes yet.
the ph levels are still the same for the last 4weeks

Sorry its my first indoor grow

Click to expand...

Your Ph may be fine.
But thats not why you change the resevoir,
You change it to get rid of the salt buildup and to add more food.
You shouldn't let your resevoir go longer than 2 weeks.
I hope you have a TDS, EC, meter if your doing hydro.
You can't just wing it, when your growing hydro.

what do thse meters check for? only knew about ph meters and light meters

StAlKeR said:

what do thse meters check for? only knew about ph meters and light meters

Click to expand...

You need a TDS (Total Dissolved solids) meter when doing hydro.
This checks to see the PPm's of how much nutrient is in the water. Everytime you feed, the PPms go down a little at a time.
Once they get below the desired reange that your plants should be getting at that stage,
you should change the resevoir completely.
New Water, and New Nutrient.
Never add.

You can do without an EC meter if your doing frequent resevoir changes.

BongJuice said:

You need a TDS (Total Dissolved solids) meter when doing hydro.
This checks to see the PPm's of how much nutrient is in the water. Everytime you feed, the PPms go down a little at a time.
Once they get below the desired reange that your plants should be getting at that stage,
you should change the resevoir completely.
New Water, and New Nutrient.
Never add.

You can do without an EC meter if your doing frequent resevoir changes.

Click to expand...

Ok then thanks for the help ill change the res now n ill look into getting 1 of them meters on ebay
Cheers