After years struggling to make a name for itself, Tonic finally struck gold – and platinum – with its debut Polydor album, “Lemon Parade,” in 1997, along with a pair of indelible rock hits, “If You Could Only See” and “Open Up Your Eyes.”

Don’t think for a second that singer-guitarist Emerson Hart, guitarist Jeff Russo and bassist Dan Lavery weren’t worried about how to sustain that momentum.

All their fears were erased with the Nov. 9 release of “Sugar,” which debuted several weeks ago at No. 81 on the Billboard 200 pop chart, while the single “Knock Down Walls” climbs the mainstream rock track chart.

“That was always in the back of our minds, having a slump,” Hart said recently, “but we really as a band tried to make a conscious decision to leave that shit at the door. We had a record to make, we love the songs, and we knew they needed tender loving care and they needed to be put down on tape organically. We didn’t want to overproduce this record.”

They buckled down because they had to: They chose to produce “Sugar” themselves.

“It scared the hell out of the label,” Hart said, “but it was a great opportunity for us. We went from one label to another, and we said, ‘We want to produce our own record,’ and they were like, ‘Excuse me?’ We know the music the best; Jack Joseph Puig, who produced our first record, his schedule was all messed up. We said, ‘We can do this. We have the studio experience, we have the knowledge of the gear.’ We brought in a great engineer (Andy Wallace), who is a friend of ours. He drove the boat while we navigated the waters.

“The only part about it that sucked was the paperwork, staying on budget, the stuff that has nothing to do with the music. That’s kind of a drag. But we got through it. We had a great production assistant, she kind of took that weight. Once we had the freedom to have play time, we were okay.”

Tonic did itself proud: “Sugar” displays the band’s progressively improving songwriting, instrumentation and vocals – from the catchy opener “Future Says Run” to the instantly sweet “Waiting For the Light to Change.”

No one-hit-album wonder here.

“We’ve always been a slow burn, slow build kind of band, and that’s always worked in our favor,” Hart said. “We’ve had some great success right off the bat with this album; people have been really receptive to the songs. I don’t have any complaints.

“I chose this business for a reason, because this is what I love to do, this is all I know how to do. That’s why I was put here, to make music, whether it’s 10 people who understand it or 10 million. The only difference between 10 people and 10 million is a lifestyle, for me, and I can adapt to anything.”

Tonic is enjoying its ride, Hart says, and though the success of “Sugar” and the band’s recent tour with the Goo Goo Dolls will only enhance their popularity, they are prepared for the future, when it all inevitably subsides.

“As a band, we’re pretty frugal,” Hart said. “We don’t spend money where it’s unnecessary. We don’t do the planes and the jets and none of us has any bad drug habits. We’re just really careful where we put our money. I keep my money in the bank and set up my retirement fund and all that shit I don’t like to think about. But that’s the reality, it’s a hello-goodbye business. You never know when it’ll end, so you have to stay on top of your toes.

“When I started this, it wasn’t for the money, obviously, because I had so many years of no money. I’m in it because I love to play. The favorite part of my day is when I have my first coffee and cigarette and pick up my guitar. When that changes, I know I have to get out.”

BWF (before we forget): Toast Tonic on the Web @ www.tonic-online.com.