Funny water chemistry

[Ken Burke]

I have three planted tanks, all in row.  A 38 gal, a 20L and a 20 T.  I use city water to full the tank, and don’t do anything other than fritz water conditioner and easy green and easy carbon.  But the ph in the 38 gal is significantly lower than the others and the nitrates are all but nonexistent, even after adding nearly 3x the suggested dose of easy green over 2 days. I’m guessing it’s because the plants have consumed all the nutrients.  What do you think?

Also, can this lead to “ old tank” syndrome if unchecked?

The 38 is moderately stocked with 3 angel fish (2 juveniles) 20 cardinal tetras, 7 ember tetras, a handful of endless, and 4 bn plecos that I’m growing out.  It is about 3 years old, and suffers from stag and black beard algae.  
 

The 20L has an adult female bn pleco, and roughly 75 to 100 juveniles that I’m growing out, and slowly selling to my lfs 

The 20T has the male  bn pleco and about 20 juveniles, plus a male betta. The juveniles in this tank are somewhat larger.
 

 

 

 

[Hobbit]

Hmmm. What kind of rocks and hardscape do you have in each one?

On 10/3/2021 at 5:08 PM, Ken Burke said:

Also, can this lead to “ old tank” syndrome if unchecked?

By “this” do you mean adding extra easy green?

[Guppysnail]

I have a similar situation. Breeding pair bn pleco + 1/2 drop babies in 20l. Another 20l 1 1/2 drop baby bn. I also 5 other tanks all same water. Bn tanks are fed more so create much higher nitrates. Food=nitrates. Plus pleco firage for biofilm and algae and are huge waste producers.  Im not sciencey but my LOOSE understanding of old tank syndrome is from not enough water changes creating poor conditions ( high bacterial load mineral depletion and high nitrates). Current fish are fine due to slow adaptations to worsening conditions. New fish added perish because they have not had time to slowly adapt to ever worsening conditions. Hope that helps. Differences in plants and how well they do from tank to tank also cause nitrate variances in my experience 

[Ken Burke]

On 10/3/2021 at 5:24 PM, Hobbit said:

Hmmm. What kind of rocks and hardscape do you have in each one?

By “this” do you mean adding extra easy green?

Larger pieces or rock are granite and slate. Large tank has a large piece of sliderwood, the other tanks have mopari or anther “big” tannin producing wood.  But are not tinting the water much.  
 

By this I meant the plants consuming all the nutrients in the water.

[Hobbit]

On 10/3/2021 at 11:42 PM, Ken Burke said:

By this I meant the plants consuming all the nutrients in the water.

Ah! I don’t have this figured out myself, so I’m curious what other people have to say, but I think usually old tank syndrome is a buildup of nutrients rather than a depletion of nutrients. But it’s possible over time you could end up with one nutrient in excess without realizing it (whatever the plants don’t use) if the ones you can measure, like nitrate and GH, stay low.

In terms of the why, I agree with @Guppysnail that one possibility is the imbalance of plecos, whether that’s because you’re feeding the smaller tanks more, or they’re eating the algae more thoroughly. Other than that it could be the plants—do the plants in the larger tank seem more established?

[Ken Burke]

On 10/4/2021 at 6:50 AM, Hobbit said:

Ah! I don’t have this figured out myself, so I’m curious what other people have to say, but I think usually old tank syndrome is a buildup of nutrients rather than a depletion of nutrients. But it’s possible over time you could end up with one nutrient in excess without realizing it (whatever the plants don’t use) if the ones you can measure, like nitrate and GH, stay low.

In terms of the why, I agree with @Guppysnail that one possibility is the imbalance of plecos, whether that’s because you’re feeding the smaller tanks more, or they’re eating the algae more thoroughly. Other than that it could be the plants—do the plants in the larger tank seem more established?

The ph in the pleco tanks is consistent with the city water…….

the bio load in the big tank is really small comparatively

 

[Dwayne Brown]

On 10/3/2021 at 2:08 PM, Ken Burke said:

Also, can this lead to “ old tank” syndrome if unchecked?

Old tank syndrome can be caused by low ph. But it is really about low maintenance and high ammonia in an aquarium. Which I doubt you have since your fish all seem perfectly happy and healthy in the photo's.

[Ken Burke]

Thanks