I wanted to get some advice/recommendations/suggestions and opinions on the ph swing and kh raise I'm experiencing in my tank.

System Details
60 gallon before gravel and aquascape(48 long x13 wide x22 high)
Fluval 405
Pressurized CO2 with Rex Reactor pushing 30ppm (green yellow drop checker) on soleniod thats starts 1 1/2 hr before the lights and stops 1 hour before the lights go off
EI type fertilization (N - 20, PO4 - 1, K - 20, iron and trace dosing). I test and adjust dosing daily.
256 watts CF 6500K/10000K on full for 11 hrs.
1-2 mm gravel with 110oz laterate and 5 lbs of Schultz Aquatic Soil for CEC.
Substrate is 4 inches thick.
Aquascape is plants and a lone piece of drift wood. Drift wood is 1 1/2 yrs old and was in the tank previously.
Tank was re-done in March. Major change was moving the tank and substrate. Prior to this ph and kh fell as system aged (which I expect).


Gravel is "inert" but a vinger test shows its not. Seems to be small shells or lots of small snails in it.

Previous gravel was larger plain fish store gravel.

Situation

1. Kh continually creeping up. On the Saturday water change it will reset to 5 but by the next Saturday its at 7. The Gh raises as well.

2. Ph is at 6.6 when the CO2 shuts off and is at 7.4 when the CO2 starts in the morning.

3. I would like "soft" water to grow some of the more exotic plants.

4. The Kh of my tap water is 3 and its ph is 7.2

5. Water change is weekly at 20 gallons.

6. I have done a 50% water change with RO and it still rose the Kh during the week.


Questions

Should I worry about the ph swing and kh raise?


I've had Limnophila hippuroides and Eustralis stellata melt away, could this be due to my conditions with ph/kh or the transition between the tank it came from and mine?


Would the Kh stop raising after a period of time?


Could an over abundance of the small nuasance snails cause Kh raise?


Should I pull out the substrate and redo? If so.. with what?


Should I set my timer to pump some CO2 in at night (like 15 minutes every 3 hours) to control the ph?

thanks,

John

Hi,

What kind of plants are you considering that require soft water? Most prefer harder water. BTW, when we talk about "hard water" we are referring to the GH.



No.


Yes, after the shells in the substrate have completely dissolved.



Possibly, but probably not. The KH is rising because of the shells that are already in the substrate.


As long as you are doing water changes, I'd say no. And anyway, the plants and fish don't care that much about the KH and pH, as long as they are not extreme.


No. In nature pH fluctuates naturally between day and night, and the plants and fish don't care.

Bill

I would like to be able to grow Eriocaulon and Tonina. These prefer a Kh under 5 from the information I've seen.

- John

One other thing, if you are doing any water top ups (without changing water), make sure you use RO, not tap water. Using RO for water changes will reduce KH initially, but the lack of KH in the water you are replacing will cause the substrate to leach KH at a faster rate than if you use tap water, so I don't think you will gain much that way.

Look, I top off many tanks with tap water. Two are non carbon tanks. So if there was a issue with months of no water changes and topping of with tap water, think I would have had problems by now. I don't or never will own a RO unit, it's just something that IMO isn't needed but does no harm either. I've grown any weed I could get my hands on and I have hard water. I think it's better to suggest a routine rather than making it a directive.

I'm not thinking RO water. I bought some from a LFS and it was about $7.00 for my water change. From my monitoring, the Kh still rose. What I am going to do is to collect rain and use it (this time of year, I can full a 30 gallon barrel in a day). My rain collection from this week has 0-1 Kh, 0-1 Gh, ph 6.6, no ammonia, no nitrites, no nitrates but a PO4 of .2-.5, so really close to RO.

Even without RO and rain water, my tap water has a Kh of 4 and a Gh of 8 so it would work well.

My problem is that my supposedly "inert" substrate is not and is breaking down causing the Kh and Ph to raise. Basically trying to decide if I can do something about it, or just "tough" it out, or replace it.

So far, I'm "toughing" it out until I come up with a better plan as its a lot of effort to change it out.

John

Wouldn't concern yourself with monitoring KH. Because you are injecting CO2, the KH has no relevance. I haven't done any testing at all for years. Keep track of your testing for a month and you will see the time spent. Not to mention the possible inaccuracies and changes made due to those inaccuracies.


Is there a problem with your tap water other than what you have listed? If not there is no reason to go to all that work.


I don't see anything that you listed as a substrate that wouldn't be classified as inert? What exactly do you mean?

My tap water would achieve my desired result if the Kh was not climbing. My current thinking is that rain would accomplish the same as RO and pull the Kh and Gh down quicker then my tap water.

I've done a vinger test and muradic acid test on my substrate. Both tests showed a reaction. Based on that with my Kh raise reach week, I'm concluding that there is something in the substate that is dissolving (likely shell bits).


John

If the goal is to try to reduce hardness, topping up with tap water will usually work against efforts to reduce hardness. I don't have this problem however, my tap water is totally soft.

If your goal is just to keep certain plants, posting more info on your setup and what happened when you tried to grow them, may show up some other more likely issues than KH.

In my initial post, I've listed information about my tank and water chemistry, the situation and questions.

The questions indicate that I've had pogo stella and limnophila hippuroides melt. I have my Kh and Gh rise through the week, which I beleive is due to something in the substrate dissolving.

I'm not sure what other information would be valuable. If you have suggestions as to what info would be valuable please ask and I'll do the best that I can to provide/answer.

I do appreciate all the help, just not sure what would be valuable.

After my 50% (30gallons) water change this weekend,
Ph = 7.0 (CO2 injection dropped it to 6.6 when plants began pearling)
Nitrate = 5 (dosed to total of 15 ish)
Gh = 7 (was 12 before change)
Kh = 5 (was 8 before change)
PO4 = .6 (dosed to total of 1.2 ish)
Ammonia = 0
Nitrite = 0
Potassium = ? (dosed 12 ppm for 55 gallons)
temp = 81
CO2 = 30ish. Ph starts over 7 each morning, starts 1 hr before the lights, and stablizes at 6.6 early in the afternoon and doesn't drop any further before turning off 1 hr before the lights.


Thanks,

John