Hanna PO4 testing

[Aquattro]

Originally Posted by Delphinus

Mine both read zero right now. Sorry Brad

Cool!! How did you manage that? You've been fighting it for years

[Delphinus]

Originally Posted by Aquattro

Cool!! How did you manage that? You've been fighting it for years

I finally added GFO,it's made a huge difference. I still see the PO4 struggling to come back but I'm changing the GFO out weekly (Brett does the same with his). Just a cup and a bit per week (well below the recommended amounts, but well above the recommended changeout period). The nice thing is that by using the Hanna tester I can tell when the GFO is spent, and that way I know I'm not wasting GFO (stuff's expensive) by changing it out weekly.

I still have the zeo going for now, but I like that I don't need to do it as much. For whatever reason the zeo was not touching PO4 in my tank. I see sort of two possibilities for this:

1) Zeo doesn't do as much for PO4 as we might think, maybe there is a problem of scale (ie., my system is closer to 400g total, but I had great results with zeo alone when the system was more like 120g total), or,

2) NO3 was reading zero for me for a long time, maybe PO4 reduction can only occur at the same time as NO3 reduction (I think it's been theorized that NP pellets work in this manner) so basically NO3 is the limiting variable, once it cannot be reduced any further, no PO4 reduction can occur.

.. just my thoughts anyhow.

PS. I also switched to 50g weekly changes, from 24g weekly changes, and this has also yielded positive results. It was apparent within 2 waterchanges that this was a good move.

[Aquattro]

Good to hear you're finally winning that battle!

[Borderjumper]

Did you put the fish back in yet? I'm thinking leaving your tank fish less for had something to do with the zero reading?

[Aquattro]

Originally Posted by Borderjumper

Did you put the fish back in yet? I'm thinking leaving your tank fish less for had something to do with the zero reading?

Half the fish were in, the rest just went in now. But I fed the tank even without fish, as I have a lot of hermits, shrimps, etc...

I've always had low readings though, but I did expect some PO4. I'll test again in a month and see what the full fish load does.

[Borderjumper]

Originally Posted by Aquattro

Half the fish were in, the rest just went in now. But I fed the tank even without fish, as I have a lot of hermits, shrimps, etc...

I've always had low readings though, but I did expect some PO4. I'll test again in a month and see what the full fish load does.

But without those big fish there was no fish poo. Anyways, I'm jealous so I will try to justify my high readings someway!

[Aquattro]

Originally Posted by Borderjumper

But without those big fish there was no fish poo. Anyways, I'm jealous so I will try to justify my high readings someway!

Last time I tested, it was really close to 0 with all my fish. Mostly I'd say the big water changes help a lot.