Seasonal pH swings in Central American waters

[duanes]

Since my tank is outdoors on the patio, and our De-Sal plant has been down for repairs for about a month, I have been using rain water for small water changes to conserve. (it is now the rainy season)
After a rain, I use tank water to flush toilets, and replace that tank water, with rain water, @ 10 gallons per day.
The pH is quite different today than during the dry season
Directly below pH during the dry season, 8 ish.

Today I did pH tests on the tank, after replacing tank water with rain water for about a month.
This arguably may be reflective of natural water conditions as rains pour down daily and inundate rivers here in Panama.

I am also anal about testing for nitrate, and wondered if it might become elevated with my smaller volume water changes, but it seems to have remained stable.

I assume this is due to the high terrestrial and aquatic plants, compared to fish ratio in the 180 gal tank.

 

[neutrino]

It would be interesting to test pH in waterways in your area. I like all the plants, there was a time I did heavily planted tanks, since then I've gone back and forth, partly depending on type of fish I kept. Nowhere to get plants near where I live now. Despite success I was never an expert at planted tanks, my method was to buy lots of plants, if some die buzz over to the lfs and buy more plants-- can't exactly do that here.

pH ranges and tolerances of various fish genera and species is an interesting subject, complicated, easy to misinterpret.

 

[TwoHedWlf]

I do 50% water changes with rainwater. I found until I put coral fingers in the filter the PH would drop very low, down to around 6. After that, it kept stable right around 7.

Well, did, I haven't actually tested PH in 10 years.

 

[Justepic]

I am also anal about testing for nitrate

Sorry, I am just too immature?

It must be amazing to live next to nature though; I am sick of living in an urban area.

 

[duanes]

It would be interesting to test pH in waterways in your area. I like all the plants, there was a time I did heavily planted tanks, since then I've gone back and forth, partly depending on type of fish I kept. Nowhere to get plants near where I live now. Despite success I was never an expert at planted tanks, my method was to buy lots of plants, if some die buzz over to the lfs and buy more plants-- can't exactly do that here.

pH ranges and tolerances of various fish genera and species is an interesting subject, complicated, easy to misinterpret.

I have tested different locations here and there when I got a chance.
I usually carry pH and nitrate reagents if expect to catch anything, or test the water in the bucket if a friend brings something over.
Lake Gatun (where I collected many of my aquatic plants) gets as high as pH to 9. (over my tests accurate range), so a guess

Yet a small stream on the island where I live, tested around 7 back in January and March back when a friend brought over some local shrimp, and my Eleotris sleeper



Tannins that drip off the surrounding foliage during the recent heavy rains are also high, tinting the water brown, and may help to contribute to maintaining the lower pH in the tank.