Dumb mistake

Rebgen · Post by **Rebgen** » Sat May 27, 2006 11:11 am

I'm sharing my mistake in hopes it will help prevent others from running into the same problem.

I started keeping RCS a few months ago in my first shrimp tank (20 gal. long). Everything has been going very well and they have reproduced very well for me.

A few weeks ago I decided to convert my son's 12 gal. Eclipse (planted) into an additional RCS tank. It was identical to my 20 gal. in most every respect...same PWC frequency, same food, same substrate. I transferred approximately 6 shrimp to the tank and acclimated them as I always have.

Within a couple of days I noticed the shrimp (especially the females) were very lethargic and gradually losing their color. Most of them just sat in my clump of java ferns and didn't roam the tank. This continued on for a couple weeks. In the meantime the female had dropped her eggs and I noticed at least five babies swimming around. The female hadn't molted though and her color was getting worse.

I stopped testing the water for anything other than nitrAtes some time ago since everything else has been so stable. I decided to test for everything again to see what might be causing the problem.

Every reading was comparable to the other tank except Ph. Normal Ph for my 20 gal. is 7.6. The Ph in the problem tank had dropped to 6.0. The kit won't allow for readings lower than that so it could have been worse. I finally discovered why the huge difference between tanks. Last year I had attatched some Java Fern to a long rock at the back of my tank. It ended up being a lime stone of some type and was dropping my Ph bigtime.

I removed the rock ASAP and did a normal 25% PWC. Within a day the shrimp began to liven up. Ph went to 7.2. That was last week. Today I did my weekly 25% PWC and noticed the females have colored back up, a couple have molted, and one has a huge cluster of eggs under her tail.

Looks like I'm back in business and the shrimp are definitely doing much better. Between reading the helpful information on this site and using a little common sense I was able to save my shrimp tank from my stupid mistakes.

Thanks and my apologies for the lenghty post.

fishgeek · Post by **fishgeek** » Sat May 27, 2006 1:46 pm

i would keep looking for your problem
limestone will react with H+ ions to increase pH not lower it

do you have any wood? carbon dioxide or other additions to your tank

andrew

Rebgen · Post by **Rebgen** » Sat May 27, 2006 4:36 pm

fishgeek wrote:i would keep looking for your problem
limestone will react with H+ ions to increase pH not lower it

do you have any wood? carbon dioxide or other additions to your tank

andrew

Thanks for the reply. The tank is low-light/low-tech with no CO2. No driftwood is in it either.

In regards to looking for the problem further....the problem was rectified almost immediately after 1) removing the rock, and 2) performing a 25% water change.

The rock was soft and could be etched with a sharp tool like a screwdriver. It was light tan and the size of a small baked potato.

All I can say is, the pH was at least 6.0 and it changed to a 7.2 shortly after the removal of the rock and the PWC. The other evidence of pH change was the change in shrimp coloration and fertility within one week of the changes.

I imagine I could test the "rock" theory by reintroducing it back into the tank and observe but that wouldn't be a very nice thing to do to my shrimp, would it?

Thanks

badflash · Post by **badflash** » Sat May 27, 2006 8:17 pm

If removal of the rcck fixed the situation, there is no need to re-introduce the problem. What ever this rockis, it isn't limestone no matter what it looks like. Limestone will increase pH above 7, not drop it below. It takes something acidic to drop the pH below 7.0

GekkoGeck0 · Post by **GekkoGeck0** » Sat May 27, 2006 11:20 pm

If you really want to test that rock out, you don't have to add it back to the tank with the shrimp. Just fill a bucket or largish container with tap water, let it stand for 24-48 hours to degas, and then add the rock. Start testing the water after 24 hours and keep testing it for as long as you like. If it really is altering water parameters dramatically, it should do it in the bucket just as well as the shrimp tank.

badflash and fishgeek are correct, limestone and its cousins raise pH, that's why it's commonly used in hard water cichlid aquaria and base rock in saltwater.

EDIT: Just a thought, how high were the nitrates in the tank prior to the removal of the rock and the partial water change? Nitrates are nitric acid, and if they build up, especially in water that has low KH (low buffering capacity), it can drop pH significantly. It happens commonly in fishless cycling.

Rebgen · Post by **Rebgen** » Sun May 28, 2006 6:55 am

GekkoGeck0 wrote:If you really want to test that rock out, you don't have to add it back to the tank with the shrimp. Just fill a bucket or largish container with tap water, let it stand for 24-48 hours to degas, and then add the rock. Start testing the water after 24 hours and keep testing it for as long as you like. If it really is altering water parameters dramatically, it should do it in the bucket just as well as the shrimp tank.

badflash and fishgeek are correct, limestone and its cousins raise pH, that's why it's commonly used in hard water cichlid aquaria and base rock in saltwater.

EDIT: Just a thought, how high were the nitrates in the tank prior to the removal of the rock and the partial water change? Nitrates are nitric acid, and if they build up, especially in water that has low KH (low buffering capacity), it can drop pH significantly. It happens commonly in fishless cycling.

Thanks for the great information. I learn volumes from all of the feedback.

In regards to the nitrates....I live in Iowa. I've tested my tap water (Des Moines river, not well H20) and it usually has elevated lebels of nitrates. Some times of the year it will test out to 40ppm. With the aid of moderately planted tanks, the water will usually test around 15 - 20.

Runoff water from farms wreaks havoc on the water supply. Phosphates and nitrates are the biggest problems. I've recently let the najas grass and hornwort grow out a little more in hopes they consume even more nitrates. It's not likely I'll ever have to add nitrates to the water.

GG, your idea with the nitrates sounds very plausible. One of the lessons I'm learning is to be more vigilant in testing ALL the parameters of my water regularly. Thanks again for all the great feedback!

badflash · Post by **badflash** » Sun May 28, 2006 10:59 am

Sounds like you should invest in an R/O unit. Costs around $200 and you can install it yourself.

Rebgen · Post by **Rebgen** » Sun May 28, 2006 1:25 pm

That might be a future option if things worsen. With the exception of this incident, all three of my tanks (2 shrimp/1 community tropical) are thriving. The one thing I am considering eventually is adding an automated CO2 system/lighting upgrade to expand my choices with plants. Right now I'm running around 2WPG with an AH Supply retro kit on the non-shrimp tank. As long as I select appropriate plants it works well.

Neonshrimp · Post by **Neonshrimp** » Fri Jun 02, 2006 11:23 pm

Hi Rebgen,

Thank you for sharing your experience so that you can help the rest of us. I hope your tank is healthy still and you enjoy the hobby.

Rebgen · Post by **Rebgen** » Sat Jun 03, 2006 8:52 am

Thanks,

The tank in question is stable and doing great. I'm glad I posted because I learned so much from all of the replies. Lot's of smart shrimp folks around this place.

CEF · Post by **CEF** » Sat Jun 03, 2006 9:14 am

I wish I had that rock, my rocks do the opposite and raise PH, but I like to keep blackwater fish. I'm not sure what my rocks leach, but it makes the shrimp kick furiously and become lethargic just like Rebgen's. I really like hardscape and hope to eventually acclaimate the population.

GekkoGeck0 · Post by **GekkoGeck0** » Sat Jun 03, 2006 4:10 pm

badflash wrote:Sounds like you should invest in an R/O unit. Costs around $200 and you can install it yourself.

The problem with RO units is that they drastically lower TDS, GH and KH (all basically linked), and a bunch of essential minerals. Great for acidic water fish and saltwater systems, terrible for regular freshwater use, unaltered. It will make the water extremely soft and you will have to readd minerals to it, or mix it with your existing water.

If you grow some of the faster growing plants, like water sprite, water wisteria, hornwort and such, you might be able to get those nitrates down much easier and cheaper than an RO unit and without the hassle of having to alter the water again just to make it suitable for shrimp.

badflash · Post by **badflash** » Sat Jun 03, 2006 4:23 pm

The problem with RO units is that they drastically lower TDS, GH and KH

You are right of course, but that is what an R/O unit is for. I use R/O Right to harden the water to what ever level I need.

GekkoGeck0 · Post by **GekkoGeck0** » Sun Jun 04, 2006 1:33 am

badflash wrote:You are right of course, but that is what an R/O unit is for. I use R/O Right to harden the water to what ever level I need.

Of course, I just wanted to make sure that it was clear to Rebgen that R/O water isn't safe to use just by itself.