[DimitriSF]

Hi folks:
7 days ago, I added a 2" male Amano shrimp, to my established, heavily-planted, CO2-injected, 30g community tank.

I'm scared of killing the little guy, during my next water change.

My aquarium water params:

• pH: 6.8; GH: 7-8; KH: 3-4; TDS: 260 ppm
• ammonia: 0; nitrites: 0; nitrates: 0; phosphates: 0
• temp: 78 F

San Francisco water params:

• pH: 8.8 - 9.8; GH 5; KH 4; TDS: 94 ppm
• ammonia: 0; nitrites: 0; nitrates: 0; phosphates: 0

SF tap water has high pH, due to municipal treatment of sodium hydroxide.

My water change routine is currently as follows, every 14 days:

• Firstly, I don't top off, and lose about 4 gallons to evaporation during this time. (The driftwood's branches prevent me from covering the tank unfortunately.)

• I dose my tap water with Prime and Nutrafin African Cichlid Conditioner (to raise GH).
• Heat water to 78 F.
• After 5 hours, water params are: pH 8.4; GH 7; KH 4; phospates 0; TDS 175 ppm
• I siphon 4 gallons out of the aquarium, while vacuming mulm, plants, driftwood.
• I add back in 8 gallons of treated water, with a water pump, within about 10 minutes' time. (By my estimates, TDS differences aside, this is roughly equivalent to a 30% water change.)

After the water change, despite the high pH, my tank pH spikes to only 7.2, and quickly settles back to 6.8 by the next day. I assume it's because I have:

• C02 injection (1.5 bps)
• Amazonia substrate
• huge piece of hornwood
• heavily planted with a variety of slow and fast growing plants

I don't want to shock the shrimp with a .4 pH spike. So, here are some strategies I'm considering:

1. Do a weekly 15% water change instead (instead of 30% in 14 days). This would hopefully cut the pH spike in half (from 6.8 to 7.0).
2. Use 50% distilled water in addition to a 15% water change. That would hopefully reduce the pH spike to just .1 (from 6.8 to 6.9). Even if I pump it in quickly, rather than drip it in, I'm hoping a .1 "spike" is tolerable for amano shrimp. Of course, I'd also make sure to re-mineralize the water back to 175 TDS.
3. Treat the new water with an acid buffer to reduce the pH to exactly 6.8. Assuming the TDS remains at 175, this would come close enough to matching my tank's water params, and I can continue my 14-day water change schedule.

Any thoughts and suggestions are much appreciated.


Dimitri

 

[Zoidburg]

If you have a buffering substrate, you shouldn't be using tap water anyway.

Don't use anything meant to change the pH such as pH Up/Down products! Not good for the tank, nor the TDS!

You could do a water change while the CO2 is off....


Amanos are pretty hardy shrimp though... and can handle a wide range of parameters - more so than cherry shrimp.

 

[DimitriSF]

Thank you for your response; I really appreciate it.

What is the reasoning behind your assertion to not use tap water + buffering substrate? It's the water I have, and I've been very successful with it. Or do you just mean that I shouldn't use it, if I want to keep shrimp?

As for not using buffering products, I agree it's not ideal. My thinking was to use a carbonate (not phosphate) buffer like Seachem's Acid Buffer, just to *temporarily* hit 6.8 pH, so I don't shock the shrimp. That wouldn't mess with the TDS too much, would it?

My understanding is that carbonate buffers are only temporary (which is exactly what I want); it gets off-gassed as CO2, over the course of a few days. So long as I re-mineralize the KH that's lost in this chemical reaction, I assume it would be relatively harmless, and not significantly effect the tank's parameters. (Am I off base in my reasoning? If so, please set me straight, as I don't want to screw up and kill the shrimp.)

As for doing a water change with the CO2 turned off, that's exactly what I already do. My tank maintenance takes about 2 hours (pruning, siphoning mulm, etc...) and my CO2 is always off during this time, and my LEDs set to low.

Now that I think about it, there may be a 4th option to consider:
4) keep my 14-day water changing routine unchanged, with 1 key difference: I'll drip acclimate the new water, over the course of the weekend. That should keep my tank parameters stable all throughout.

 

[aotf]

How old is this tank?

I’m echoing Zoidburg here but the tap will burn out the ADA and then your pH will creep up to tap levels with every water change.

I’m also in SF, same tap water params, did something similar with ADA and CO2. After 6-8 months, my pH starting climbing. A couple months later, it was in the pH 7.6+ range.

 

[DimitriSF]

How old is this tank?

8 months.

...the tap will burn out the ADA and then your pH will creep up to tap levels with every water change.

I’m also in SF, same tap water params, did something similar with ADA and CO2. After 6-8 months, my pH starting climbing. A couple months later, it was in the pH 7.6+ range.

My tank's pH hasn't spike yet, but perhaps it's because it has 2 bags of Amazonia in there. Also, other things in the tank are probably helping to buffer the water, thus slowing the depletion of the substrate's buffering life. Namely:
1) my tank's comically huge piece of driftwood;
2) my injected C02;
3) I only do a 30% water change every 2 weeks (so less new water that needs to be buffered).

Even if the Amazonia soil eventually loses all its buffering capacity, that would be a blessing. It means that my water would shift from 6.8, to a more long-term pH somewhere in the 7 range. Anything above 7 means I can easily mix my tap water with distilled water to naturally target the 7.4 pH without using chemical agents.

 

[corgifishkeeper]

I live in San Francisco too, If you treat the water with prime and let it sit for a day the ph will drop to the low 7, that way when you mix with your tank, it will not have a big swing. I usually set aside a 5 gallon bucket of water for a day or two before my water change, you might want two bucket if you are adding 8 gallon, or do 4 gallon weekly vs 8 gallon every other week, that way you will have a very small change to parameters.

 

[DimitriSF]

Thanks for the advice. I'll have the water sit for a few days, before I do my next water change. (I'll wait to dose the Prime though, until the last day, to make sure it doesn't lose its detoxifying effects.)

 

[aotf]

I'm not super clear on the exact chemistry but buffering substrates (very popular in the shrimp community) keep kH at 0 and pH low. I'm not sure how they're "absorbing" carbonates in the water but if you continue to add more (e.g by adding tap water with a non-zero kH), the substrate will eventually exhaust its finite ability to keep the kH down. The result of this is that the pH will rise.

A common issue beginners in the shrimp community have (I did it too) is that they gravitate towards Amazonia because plants love it but they don't realize it will buffer their tap water so low. It becomes an issue for certain species (neocaridina) that don't like the pH that low but isn't usable for others that do because the tank is a pH time-bomb.

If you're fine with your pH rising (it sounds like it'll make your life easier, actually), then just keep doing what you're doing and you'll eventually get there. In the meantime, I agree that your best solution is probably just a slow drip acclimation. That way, you don't have to try to manipulate different parameters of the water or temporarily buffer in one direction or other. It will be tedious but overall probably safer and won't require micromanaging the system against wild swings.

 

[DimitriSF]

Thanks aotf, for the follow up and advice.

In the past, I made the mistake of introducing delicate shrimp, then doing a large, fast water change, with very cold water! The results, as you'd imagine, weren't good: they all promptly molted and died. Not my finest hour.

...I agree that your best solution is probably just a slow drip acclimation.....It will be tedious but overall probably safer and won't require micromanaging the system against wild swings.

At first, I thought drip systems would be tedious too, but now that I've set one up, in these last 2 days, it's actually easier to do water changes now.

My routine used to be to treat and heat tap water, in a plastic tub in my garage, using a pump, inline heater, and 30' hose. Then, after 6 hours, take one end of the hose, drag it into my office, and clamp it onto the aquarium. Then, detach it and drag it back.

Now, I've attached an airline tube over my tank, with a plastic drip irrigation valve on the end:
https://photos.app.goo.gl/DJ2ssOVth4qLiYyI3

Via a tiny drilled hole, in the adjoining wall of my garage and office, I ran it through and spliced it into the 30' hose circulating in my plastic tub:
https://photos.app.goo.gl/qOZWQxEVkHQdm3Ox1

Done!


Whenever I turn on the pump+heater, it circulates/heats the water inside the cooler. The back pressure is more than enough to push water up through the airline tube.

 

[aotf]

Very cool! That’s a neat solution.

Your old regimen sounds back-breaking. Makes my nano tank water changes sound fun!