Backyard Aquaponics
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Changing grow media in the middle of a cycling process because of a limestone suspecting in the grow media that affect the raise in pH of water -is this helpful ?

Changing grow media in the middle of a cycling process because of a limestone suspecting in the grow media that affect the raise in pH of water -is this helpful ?

I'd let it be, you're trying to build up the bacteria on the rocks, now is not the time to switch gravel in the beds you already have (especially since you really don't know if this is limestone).

Many systems start out with high pH and over time it lowers. If you are worried about the gravel, you should consider using a different media for any NEW growbeds, one that will not affect the pH.

[what he said ^]

Your media is where most of the nitrifying bacteria live, so changing it will almost stop your processing of ammonia and nitrites.

I would add a new grow bed full of a neutral media, and keep both going until your system settles down.

As a temporary fix I think you can add a few drops of lemon juice, but don't take my word for that. Do a search for lemon juice or adding acid. I don't think it lasts very long though.

I did some experiments with charcoal a while ago but it's always a bit dangerous to add unknown's to the system.

http://www.backyardaquaponics.com/forum/viewtopic.php?f=1&t=7430&hilit=+charcoal

To test your media to see if it it causing your high pH put some of the more suspect looking (limestone looking) bits into some vinegar. If it fizzes then you know.

I have only tested my system once. It was 8. As it is new - about 6 weeks old - I haven't worried about it. I just feed sparingly so I don't have too much ammonia in the system. So far all 100 trout are doing fine and so are the plants.

If you keep testing you find something to tinker with then you will cause a problem and lose everything.

Once the bacteria really get going the pH will come down as I believe they will produce nitric acid when converting things. When this happens you may need to add some shell grit to keep the system buffered. This is better than adding acid.

Adding things usually cause quick swings which is worse. Slow, natural changes are best.

is this correct-
adding floating raft beds is the same as adding gravel grow bed to balance the ratio between fish tank to grow bed ratio. does this help in balancing the system.

No. A floating raft bed does not give the same surface area (ie the gravel) for the beneficial bacteria to grow on.

It will do very little, if anything to help with the ammonia and nitrIte levels (both of which can kill your fish). It will reduce your nitrAte levels as you have extra plants.

I dont know why people talk about growbed to fish tank ratio. It should filtration to fish ratio.

For every 100 litres of filtration you can have 3kg of harvest size fish. Ie if you are harvesting your fish at 500g, you can have 6 fish per 100 litres of filtration

Note: this is absolute maximum and a new system should run less.

ah ok. how about tower grow bed. i'm thinking several of them in the sides, what do u reckon, i have a little space area you know.

Just to update
Its Day 23
ammonia = 0.25ppm
nitrite = 0.5ppm
nitrate =40 to 80ppm
pH =8.4
fish = 20 pcs
FT = 200liters
gb = 40liters (planning o add more)
growmedia = charcoal/gravel
temp = 24C

i added water with pH = 6.4 (about 12liters) to the FT, does not have much effect after 2 hours,
pH still 8.4

i see a big brown grow-bed looking box in that pic

With 20 fish, if you are planning to harvest them at 500 grams, you really need about 400 litres of growbed.

Tower systems will help.

You are just very lucky those are tilapia since most other types of fish wouldn't have survived. Looks like you are doing fairly well at the moment but you definitely need to get more grow beds online before the fish grow much.

Don't stress about the nitrate levels, tilapia can handle those way off the chart just fine for quite a while. Just keep your ammonia level down as long as your pH is still up, keep using rain water to top up and hopefully in time the pH will come down a bit. Test any new media to make sure it won't affect pH.

Good Luck.

thanks guyz

i'm having problem with the box below, i cannot make it a growbed cause i have
no location for mt sump
so i'm planning to use the box as the sump for additional grow beds.

i have a picture below that i modified for u to see what i'm planning to do.
propose additional grow will be 6 x 20liters =120liters plus the existing 40liter GB =160 liters.
i'm planning to add tower GB in he future.

Yes those red tilapia are tough..

Good day guyz,
I just found out, that the cause of the rise in pH of the water in FT, it is not the gravel that i'm suspecting but the charcoal.
I have tested the tap water before introducing a gravel and charcoal separate container. tap water pH =7.4
Then i put the media in the container with water, after 2 days tested the water from the container with gravel pH=7.4 and
the water in the container with charcoal reads pH=8.8.
I'm planning to add more grow bed with the sump below.just like in the photo.
Thanks